The Heart, The Seat of Indwelling Sin
By John Fast
In our last study we considered indwelling sin as an internal law or principle and the properties which rightly make it a law; that is, its power and effectiveness. In a true Christian the law of indwelling sin has lost its power, “knowing this, that our old self was crucified with Him, that our body of sin might be done away with, that we should no longer be slaves to sin” (Rm 6:6). However, even though sin has lost its ruling power in a believer, it has not lost its nature. It is still a law. Its power is weakened, but not nullified or destroyed. It is a principle that is still “present in me” (Rm 7:21).
The effectiveness of the law of sin resides in its ability to bring compliance by means of its offered rewards and its threats of punishment. The “passing pleasures of sin” (Hb 11:25) are its promised and deceitful rewards which leads to the actual commission of sin. Whereas its threatened and perceived punishments lead to sins of omission, especially when obedience to God’s word threatens a person’s cherished lusts, idols, and temporal and worldly interests. They neglect the good and choose the easy, expedient, and superficial.
Because the law of sin is an inward and inbred law, this gives it certain advantages. First, it is always present, which makes constant and vigilant watchfulness against its deceptions necessary, “Watch yourselves, that you might not lose what we have accomplished, but that you may receive a full reward” (2 Jn 8). If the five foolish virgins had been more alert, and not been so negligent, they would not have been excluded from the kingdom of heaven (Mt 25:1-13). “Be on the alert then, for you do not know the day nor the hour” (Mt 25:13).
Second, being an inward law, the law of sin is always ready to assert itself into whatever we do. All it needs is an opportunity, “for sin, taking opportunity through the commandment, deceived me, and through it killed me” (Rm 7:11). This is why the Christian is to “make no provision for the flesh in regard to its lusts” (Rm 13:14); why he/she is to “flee immorality” (1 Cor 6:18); “and do not participate in the unfruitful deeds of darkness, but instead even expose them” (Eph 5:11). Yet how many professing Christians make the evil deeds of darkness the primary source of their entertainment? How many use their professed Christian freedom as an opportunity for the flesh and a cloak for their sin (Gal 5:13; 2 Pt 2:19)?
Third, indwelling sin is always effortless. It is “the sin which so easily entangles us” (Hb 12:1). It needs no special conditions. It needs no help or encouragement. It easily worms itself into all we do, to oppose God and His word and to promote evil and sin.
Since indwelling sin is an inward and inbred principle, where does this law reside within us? The Bible declares throughout that the seat and subject of the law of sin is the heart. This is where indwelling sin lives. This is its fortress. This is what gives it strength and power. This is the subject of its operations. It has invaded and occupied what rightfully belongs to God. The fallen human heart is the source of all the evil which appears in the world, “For out of the heart come evil thoughts, murders, adulteries, fornications, thefts, false witness, slanders,” (Mt 15:19). “Furthermore, the hearts of the sons of men are full of evil, and insanity is in their hearts throughout their lives” (Eccl 9:3); “…the intent of man’s heart is evil from his youth” (Gn 8:21).
One would think that if anything should debunk the popular notion that the human heart is basically good and inclined toward good, it would be the exceedingly evil nature of the days in which we now live. But instead of placing the blame where it rightly belongs – the evil human heart – virtually all the evil today is ascribed to be the result of external factors such as social, political, educational, and economic disadvantages. If these inequities and deficiencies could be corrected, we are told, evil would be curtailed.
This superficial and self-deceived assessment of the cause of evil deals only with the symptoms not the disease. If the torrent of evil is to be stemmed, it must be arrested at its source, and only God can change the human heart. Herein lies the greatest hindrance to true salvation. Here is what makes the path to life narrow and the gate to heaven restricted and difficult. A person must be born again (Jn 3:3). We need new, not reformed and renovated hearts. It is easy to reform your life, but only God can change your heart. When the disease is left undiagnosed and therefore untreated, it only grows worse and worse. Increasingly, law and order must be maintained by oppression and totalitarianism.
While it is true that there may be many outward temptations, aggravations, and provocations that excite and stir people up to acts of evil, these do nothing more than provide an excuse and opportunity to let out what was in the heart before. Temptations and opportunities put nothing into the heart, but simply draw out what is already there.
We often hear of people, especially pastors, who, we are told, “suddenly” fall into some gross sin. They had a “moral lapse”. Their actions were out of character for who they really are. They are really a good person. Those who make such statements and extenuate such “moral lapses” reveal they have a deficient understanding of the human heart. Nobody “suddenly” falls into sin. People fall when preparation meets opportunity. They had already prepared their heart for their sin, “But each one is tempted when he is carried away and enticed by his own lust” (Jm 1:14). The temptation and opportunity met a prepared heart; it simply drew out what was already there.
This is the entire work of the law of sin, and where it works, lives, and operates is in the heart. The evil which a person commits is “from the evil treasure” of his heart (Lk 6:45). The treasury is the heart and the “treasure” is the dominant moral principle in a person. The dominant moral principle in “a good man”, that is, one who has been born again, is “the good treasure of his heart” from which “good” ensues (Lk 6:45). The “good treasure” is the ruling principle which is constantly motivating and producing actions that are of the same kind and nature as itself, just as every good tree bears good fruit and every bad tree produces bad fruit (Mt 7:17, 18).
Jesus calls this indwelling principle a “treasure”, whether it is good or evil, because of its abundance. It is inexhaustible. The more it is used, the more it grows. The good person does not diminish his good treasure by using it, but rather grows it by exercise. The more a Christian exercises obedience to God’s word and walks in a manner worthy of their calling (Eph 4:1), the more they grow in Christlikeness. The more someone exercises their indwelling sin and obeys its lusts, the more it increases in them.
The more a person sins, the more they are inclined and motivated to sin. Sin is an evil treasure that increases by doing evil. Every sin increases the principle of sin and fortifies the habit of it. Today we call this reinforced habit of sinning an “addiction”. This is part of the deceitfulness of sin in that people will deceive themselves that if they gratify their sinful lusts and desires then they will not need to sin anymore. An addict tells themselves they will stop after one more fix; a drunkard tells himself he will stop after one more drink; the greedy and discontent person needs to accumulate just a little more or acquire one more thing, and on and on it goes, regardless of the specific lust. Sin feeds upon itself, “For just as you presented your members as slaves to impurity and lawlessness, resulting in further lawlessness,” (Rm 6:19; cf. 2 Tm 2:16). Lawlessness increases the treasure of lawlessness, and ungodliness increases the treasure of ungodliness, thereby reinforcing the habit and principle of sin. It is the immutable biblical principle of sowing and reaping (Gal 6:7, 8).
And where is this treasure stored, where does it live? It is stored and lives in the heart where no earthly or angelic power can touch it or dislodge it. It lies safely and securely kept in the heart, growing and increasing until a power greater than itself arrests it at its source, dislodges it from its fortress, and unseats it from its throne.
But what is the heart? The heart of man is the worst part of him before God regenerates it, and the best part after it is regenerated. The word “heart” is the most important term relating to man in the Bible. The eye of God is fixed on the heart, “for man looks at the outward appearance, but the Lord looks at the heart (1 Sm 16:7); “You are those who justify yourselves in the sight of men, but God knows your hearts;” (Lk 16:15).
The word “heart” is sometimes used for the mind and understanding, “their foolish heart (i.e. mind, understanding) was darkened” (Rm 1:21; cf. Dt 8:5; Is 6:10; Jer 7:10). Sometimes for the memory, “Your word I have hid in my heart” (Ps 119:11). Sometimes for thinking and deliberation, “And Jesus knowing their thoughts said, ‘Why are you thinking evil in your hearts” (Mt 9:4; cf. Lk 9:47). Sometimes for the conscience (1 Sm 24:5; 2 Sm 24:10), and sometimes for the affections as they like or dislike, are attracted to or have an aversion for something or someone. When someone takes pleasure in what they do and are fully committed either to God or to their idols they are said to follow and obey with a “whole heart” (2 Kg 20:3; Is 1:5).
The heart is the seat of all our thoughts, will, desires, affections, and actions. It judges between right and wrong, good and evil. From the heart “flow all the springs of life” (Pv 5:23). It is the fountain of all that is good or evil. If the fountain is polluted, all that flows from it will be corrupted. The heart is man’s “mission control” center. The emotional aspect of the heart and a person’s feelings, which today are placed at the forefront, are, in the Bible, always in the background.
It is here, in our hearts, where our enemy of indwelling sin lives, hides, and operates. This is its fortress from which it keeps up its sustained rebellion against all that is God as long as we live. It has more success at some times than at others, but as an enemy it is always in rebellion to God. The very nature of our hearts contributes to the strength and power of indwelling sin. The heart supports the most suitable conditions for indwelling sin to prosecute its rebellion. What are these attributes which make the heart an ideal citadel for indwelling sin? Jeremiah 17:9 describes three of them, “The heart is more deceitful than all else and is desperately sick; who can understand it?”
First, the heart is “deceitful”. The Hebrew word is aqob, and means “sly; slippery; devious”. Not only is the heart deceitful, but it is “more deceitful than all else”. Its deceitfulness is unmatched by anything or anyone. It is the most crafty, wily, and subtle cheat of all. It deceives us as Jacob did his father Isaac and his brother Esau, his name being derived from this word aqob (Gn 27:36). There is a great deal of deceit in the world, but nothing is more deceitful than our own heart. The world is full of deceit and fraud, but it is nothing in comparison to the deceit within our own heart. It is a terrible thing to be deceived by others, but to be self-deceived is the most terrible of all. The Laodiceans thought they were “rich, and have become wealthy, and have need of nothing”, never imagining they were really “wretched and miserable and poor and blind and naked” (Rv 3:17). Their own self-assessment could not have been further from their true condition. They were blinded to their true condition by their own false appraisal. They had deceived themselves into thinking they were one thing when they were really quite another, “…you have only deceived yourselves” (Jer 42:20). We can deceive ourselves and others, but we cannot deceive God.
The deceitfulness of the heart lends great strength to the law of sin. Deceitful sin resides in a deceitful heart. No wonder the Bible warns, “He who trusts in his own heart is a fool” (Pv 28:26). There is nothing of which we should be more suspicious and untrusting than our own heart. Yet today most are advised to “trust your gut”; “trust your feelings”; “follow your heart”. Such advice is not only unbiblical, it is deadly.
There are two primary reasons why the heart is “more deceitful than all else”. The first is that our hearts are self-contradictory. For instance, if someone condemns the violent actions of an Islamic terrorist as inconsistent with true Islam, their denunciation is applauded. But if someone says that homosexuality, immorality, abortion, and worldliness in general is inconsistent with Christianity, and those who support and practice such things are not true Christians (1 Cor 6:9, 10; Eph 5:5; 1 Jn 3:4-10), they are condemned as judgmental and unloving. On the one hand they feel free to disavow someone’s profession of Islam based on their actions, but on the other they condemn those who would apply the same standards to someone’s claim of being a Christian. The mind, will, and affections are no longer working in harmony, but often contrary to one another. More often than not the emotions, which should be controlled by the mind and will, end up leading and dominating both. People will be passionate and excited over the prospect of earthy gain or their temporal and worldly interests, but cold and indifferent to things that pertain to their eternal condition. They may get heavily involved in religious activities, but have little interest in the great truths of the Bible. People will hold multiple contradictory opinions at the same time, thinking all of them are true. They profess the Bible is authoritative and sufficient, but live as if their own opinion and experience trumps the Bible. They profess they believe in and know God, but by their deeds they demonstrate they neither believe nor know Him (Tit 1:16; Jm 2:19, 20). People will take great risks and expend much effort for a little earthly fame and fortune, or even a cheap thrill, but exert virtually no effort, take no pains, or deprive themselves of one thing for the sake of their souls. How hot and eager are people’s affections for the things of this world, and how cold and careless towards things eternal. How watchful and diligent are most people for their worldly interests, but how negligent and indifferent towards heavenly things. People will, if they can, shun and be fearful of anything that poses a danger and threat to their life and property, but how they voluntarily and continuously expose themselves to things that pose the greatest danger to their souls. This self-contradiction makes the heart deceitful above all else.
The second reason is that the heart is full of false promises, resolutions, and intentions. How many times has someone vowed, “one more time and I’ll quit”. How often have you resolved to spend more time in prayer and reading God’s word, to walk by faith and not by sight, to give up some vice or bad habit, to be a better husband; wife; father; mother? People deceive themselves into thinking that because they have intended to do something they have actually done it. Hell will be full of people who were good intenders, but poor practitioners. The heart is not only deceitful, but deceived. It uses all its deceits in the service of sin and to promote the interests of sin. This is why the Bible cautions us to watch over our hearts “with all diligence” (Pv 4:23). Watchfulness is required because there are old and new strategies which the law of sin employs to entice and deceive our hearts.
Secondly, not only is the heart deceitful, but it is incurable. This is what is meant by its being “desperately sick”. The same Hebrew word is used in Jeremiah 30:12, “Your wound is incurable, and your injury is serious”. The heart is infected with an incurable spiritual disease; the law of sin. It never goes away, it is always ready to act, and it always acts effortlessly. The law of sin lives and operates in a heart that is incurably infected with sin. It is comfortable, content, and at home in the heart with nothing to disturb it until it is supplanted by a new principle, “the law of the Spirit of life in Christ Jesus” (Rm 8:2). Then the flesh goes to war against the Spirit, “the flesh sets its desire against the Spirit, and the Spirit against the flesh, for these are in opposition to one another,” (Gal 5:17). A true Christian can no longer sin comfortably, contentedly, and habitually (1 Jn 3:8, 9; 3 Jn 11).
The third attribute which makes the heart an ideal home for sin is that it is unknowable: “who can understand it?” Who can understand the heart? “I, the Lord, search the heart, I test the mind” (Jer 17:10). The heart is unknowable and unsearchable by anyone but God. Only God knows the inner workings and dark recesses of the heart. All but God are ignorant of the true condition of their heart, “but God knows your hearts” (Lk 16:15). Only the word of God is “able to judge the thoughts and intentions of the heart” (Hb 4:12). Sin has secret hiding places in the heart, subtle subterfuges to conceal itself, false and respectable names with which to disguise itself, and counterfeit resemblances of true faith. The word of God applied by the Spirit to the heart, mind, and conscience discovers and exposes all these for what they really are. This is why “everyone who does evil hates the light, and does not come to the light”, because if they did, “their deeds should be exposed” for what they really are (Jn 3:20). Most people today assume they have a “good” heart; that it is not as bad as the Bible describes it to be.
Herein lies the strength of the law of sin, it lives and operates in a deceitful, incurable, and unknowable heart where it cannot be searched out and discovered. We might think we have conquered a particular sin, but it is only hiding and waiting for a better opportunity. All we can do is to diligently watch for it to come out of hiding and oppose it at its first appearance. A Christian’s work of contending against and crucifying the sin in their life is never finished until death, “let us cleanse ourselves from all defilements of flesh and spirit, perfecting holiness in the fear of God” (2 Cor 7:1). This is the duty of every Christian, to “be careful how you walk, not as unwise men, but as wise, making the most of your time, because the days are evil” (Eph 5:15, 16).
Given that the seat of indwelling sin is in hearts such as ours, what should this tell us? First it should tell us that the work of opposing and killing sin in our own life is never over while we live in this world. We have to deal with a fallen flesh, a wicked world, and a busy devil as long as we live. We can never ease up. Spiritual laziness and self-confidence have been the ruin of untold numbers of professing Christians. If we slacken in our diligence we will soon see this enemy appear from hiding and exert itself with renewed energy and persistence. The only way to do this work is to keep doing it.
Second, if indwelling sin resides in hearts so deceitful – “more deceitful than all else” – this requires vigilant and constant watchfulness. We can never let down our guard and become complacent or presumptuous. We must always flee and avoid, not indulge or accommodate, what the Bible tells us to flee from and avoid (1 Cor 6:18; 10:14; 1 Tm 6:11: 2 Tm 2:16, 22). “Do not enter the path of the wicked, and do not proceed in the way of evil men. Avoid it, do not pass by it; turn away from it and pass on” (Pv 4:14). If David had fled instead of lingered when he saw Bathsheba bathing he would not have committed adultery and tried to cover it up with murder. Lingering led to adultery which led to murder. One sin led to another. We need to practice a healthy distrust and suspicion of our own hearts. We need to be acquainted with Satan’s devices (2 Cor 2:11). The more diligently we watch over our hearts and kill sin the more sin is weakened. The reverse is also true, the more we allow, justify, redefine, ignore, and practice sin, the stronger it becomes. “Therefore let him who thinks he stands take heed lest he fall” (1 Cor 10:12). Sadly, very few today are taking heed to themselves.
Third, we must commit our lives to the One who can search the heart and root out sin. Like David we need to pray, “Search me, O God, and know my heart; try me and know my anxious thoughts; and see if there be any hurtful way in me, and lead me in the everlasting way” (Ps 139:23, 24). David desired to know of any hurtful way that was lurking in any treacherous corner of his heart, and how to prevent and expose all its deceits. It must be a sincere request, not harboring some favorite sin, or some sin you would never commit but enjoy thinking about. You can provide no sanctuary or safe haven in your heart for any sin. To do so is to have an insincere hatred of sin. It means you still love sin. It means that sin still has its dominion over you and is the ruling and governing principle in your life. You have not laid aside “the old self which is being corrupted in accordance with the lusts of deceit” (Eph 4:22).
All lusts are deceitful lusts. All deception is dangerous. Self-deception is more dangerous. But self-deception in things pertaining to salvation is the most dangerous of all. Just ask those poor professing Christians in Matthew 7:21-23. Just ask the Laodiceans (Rv 3:17).
The seat of the law of sin is the heart, but the heart is also the seat of the Holy Spirit in every true Christian, which dethrones the law of sin as the heart’s governing principle. As such, every Christian has been “renewed in the spirit of your mind, and put on the new self, which in the likeness of God has been created in righteousness and holiness of the truth” (Eph 4:23, 24). Nothing proves the sincerity of our faith more plainly than our behavior and attitude toward the sin which dwells within us before, or under, or after the commission of it. It is in this that “the children of God and the children of the devil” are made evident (1 Jn 3:9).
In our next study on indwelling sin we will examine five distinguishing signs pertaining to sin that differentiates and denotes the spiritual state of a person.