It is not the person, which is a formal and psychological concept, but the heart of man, which represents a spiritual, ethical concept, that is regenerated.
Scripture very frequently speaks of the heart, and although in Scripture the terms spirit, soul and mind (nous) are sometimes interchanged, yet in general we may say that by heart Scripture usually denotes that spiritual, ethical center of man that in regeneration is radically turned about.
That it is the heart that is regenerated is directly taught in Scripture. Thus we read inconcerning the new covenant which God will make with His people in the new dispensation: “Behold, the days come, saith the Lord, that I will make a new covenant with the house of Judah: Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the Lord: But this shall be the covenant that I will make with the house of Israel; After those days, saith the Lord, I will put my law in their inward parts, and write it in their hearts; and I will be their God, and they shall be my people. And they shall teach no more every man his neighbor, and every man his brother, saying, Know the Lord: for they shall all know me, from the least of them unto the greatest of them, saith the Lord: for I will forgive their iniquity, and I will remember their sin no more.” Cf. . And in we read: “Then will I sprinkle clean water upon you, and ye shall be clean: from all your filthiness, and from all your idols, will I cleanse you. A new heart also will I give you, and a new spirit will I put within you: and I will take away the stony heart out of your flesh, and I will give you an heart of flesh. And I will put my Spirit within you, and cause you to walk in my statutes, and ye shall keep my judgments, and do them.”
Now the heart, according to Scripture, is the center of our entire existence from a spiritual, ethical viewpoint. Just as in a physical sense the heart is the center of our physical existence, the fountain whence issues the blood that courses through our veins, so in a spiritual sense the heart is the center of our entire life; the spiritual, ethical direction of all our thinking and willing, of all our desires and aspirations, of all our thoughts and inclinations, is from the heart. Not the thoughts and desires and aspirations as such, from a psychological point of view, issue from the heart: for the soul is the seat of intellect and will. But it is the heart that gives to them their spiritual, ethical direction, that is, the direction either toward God or toward the devil, toward righteousness or unrighteousness, toward good or evil. If the heart is good, all our thoughts and intents and aspirations and desires are good in principle. But if the heart is evil, all the issues of our life are evil.
This is plainly taught in holy writ.
Thus the Lord teaches us in, “Either make the tree good, and his fruit good; or else make the tree corrupt, and his fruit corrupt: for the tree is known by his fruit. O generation of vipers, how can ye, being evil, speak good things? For out of the abundance of the heart the mouth speaketh. A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things.” And in the Lord Jesus teaches His disciples as follows: “Do ye not yet understand, that whatsoever entereth in at the mouth goeth into the belly, and is cast out into the draught? But those things which proceed out of the mouth come forth from the heart; and they defile the man. For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies: These are the things which defile a man: but to eat with unwashen hands defileth not a man.” Cf. .
This is taught in many passages of holy writ. According to, the Lord God “saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually.” Cf. . In we read that the Lord God made His covenant with Israel and with their children, warning them “lest there should be among you man, or woman, or family, or tribe, whose heart turneth away this day from the Lord our God, to go and serve the gods of these nations; lest there should be among you a root that beareth gall and wormwood; And it come to pass when he heareth the words of this curse, that he bless himself in his heart, saying, I shall have peace though I walk in the imagination of mine heart, to add drunkenness to thirst.” In I Chronicles we read that David blessed the Lord before all the congregation of Israel, after they had willingly offered their gifts for the building of the temple, and he prays: “O Lord God of Abraham, Isaac and of Israel, our fathers, keep this forever in the imagination of the thoughts of the heart of thy people, and prepare their heart unto thee.” . Scripture speaks of a broken and contrite heart, ; ; ; ; of a clean heart, ; ; of a perfect heart, ; ; ; ; ; ; ; ; ; of a pure heart, ; ; ; ; ; ; of an understanding heart, ; ; ; ; ; of an upright heart, ; ; ; of a willing heart, ; ; ; of a wise heart, ; ; ; of a whole heart, ; ; . But on the other hand, it also speaks of a heart that is bitter, ; of a double heart, ; of an erring heart, ; ; of a fickle heart, ; of a foolish heart, ; ; of a heart that is hardened, ; ; ; ; ; ; ; ; ; , and many other places; of a perverse heart, ; ; ; ; of a proud heart, ; ; and of a wicked heart, ; ; ; .
From all this it is very evident that according to Scripture the heart is the center of man’s life from the spiritual, ethical viewpoint. It follows that if the heart of man is foolish, erring, fickle, perverse, and wicked, all the issues of his life are such; while, on the other hand, if the heart of a man is pure, upright, perfect, understanding, wise, and willing, all the issues of his life from a spiritual, ethical viewpoint are directed in the way of the precepts of the Lord our God.
This heart is regenerated. In order to understand what is meant by the new and the old man in the Christian, we must remember that it is specifically the heart, the center of man’s life from a spiritual, ethical viewpoint, that is regenerated. It is not man’s nature that is regenerated. For to that nature belong both body and soul. On the contrary, the present nature, the present body and soul, belong to what the apostle Paul calls inthe outward man, which perishes, while the inward man is renewed day by day. The Christian still has his old body. And that body is earthy, corrupt, and subject to death. It will not be regenerated until the moment of the resurrection. Neither is the principle of regeneration as such in the soul, in the intellect and in the will. Certainly our present intellect and will are not heavenly, but earthy. Although, of course, it is true that from the principle of the regenerated heart the whole nature is affected, nevertheless it is only the heart that is regenerated. And that regenerated heart affects the whole man. That heart is holy, and principally the whole new man is holy. The Christian is not a man that has two hearts, a wicked, perverse heart and a holy and upright heart. For though the Christian feels sometime as if his heart is still unholy and wicked, and loosely speaks of his wicked heart, principally this is not true. He has only one heart, and that heart is holy.
Now the new man is the regenerated Christian as he lives in this present nature, with mind and will and all his desires and aspirations, and that too in the midst of the present world, which offers no contact whatever with the principle of regenerated life, in which, on the contrary, everything is against that regenerated Christian, for in that world is the lust of the flesh, and the lust of the eyes and the pride of life,—the new man, I say, is the person of the regenerated Christian as he lives from the principle of regeneration, and that too according to the Word of God. For while the regenerated life has no contact with the present world, the Word of God reveals unto him a new world in Christ Jesus our Lord.
And what then is the old man?
It is the same person of the Christian as he still lives not from the principle of the regenerated heart, but from his old nature. In Scripture this old nature of the Christian is frequently called the flesh, as over against the spirit.: “There is therefore now no condemnation to them which are in Christ Jesus, who walk not after the flesh, but after the Spirit.” And again, in : “That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit.” That flesh is carnally minded, and is enmity against God, : “For they that are after the flesh do mind the things of the flesh; but they that are after the Spirit the things of the Spirit. For to be carnally minded is death; but to be spiritually minded is life and peace. Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be.” And again, in the same chapter, : “Therefore, brethren, we are debtors, not to the flesh, to live after the flesh. For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live.” And to quote no more, in we read: “This I say then, Walk in the Spirit, and ye shall not fulfill the lust of the flesh. For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would. But if ye be led of the Spirit, ye are not under the law. Now the works of the flesh are manifest, which are these: adultery, fornication, uncleanness, lasciviousness, idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies, envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God. But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, meekness, temperance: against such there is no law. And they that are Christ’s have crucified the flesh with the affections and lusts.” Moreover, this old nature is also called the body, and the members of the body. In we read: “Let not sin therefore reign in your mortal body, that ye should obey it in the lusts thereof.” And in : “Neither yield ye your members as instruments of unrighteousness unto sin: but yield yourselves unto God, as those that are alive from the dead, and your members as instruments of righteousness unto God.” Flesh and body and members of the body the old nature is denominated, not because sin is something material, or has its seat in the body, but because, in the first place, soul and body are inseparably connected; and in the second place, because sin manifests itself in the present world through the deeds of the flesh and the deeds of the body. In this old nature the Christian is born. For by nature we are conceived and born in sin. Moreover, that old nature is very old indeed. It comes down in every individual from Adam and Eve in paradise. The result is that in that old nature, in that flesh, in that old body, there are deep ruts of sin, indelible habits of sinful inclinations, of sinful desires, and sinful thoughts. And just as the present world in its lust of the flesh and the lust of the eyes and the pride of life is opposed to the Christian as he is regenerated, opposed to the new man, so everything in the present world is in favor of the old man. The world, the devil, and our own flesh, therefore, unite in opposition against the new man in Christ.
And thus it happens that the new man, the person of the believer as he lives from the regenerated heart, has a continual struggle. Of that struggle the apostle Paul speaks in, ff.: “For that which I do I allow not: for what I would, that I do not; but what I hate, that do I. If then I do that which I would not, I consent unto the law that it is good. Now then it is no more I that do it, but sin that dwelleth in me. For I know that in me (that is, in my flesh) dwelleth no good thing: for to will is present with me: but how to perform that which is good I find not. For the good that I would I do not: but the evil which I would not, that I do. Now if I do that I would not, it is no more I that do it, but sin that dwelleth in me. I find then a law, that, when I would do good, evil is present with me. For I delight in the law of God after the inward man: But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members. O wretched man that I am! who shall deliver me from the body of this death? I thank God through Jesus Christ our Lord. So then with the mind I myself serve the law of God; but with the flesh the law of sin.”
Even from this language it is very apparent that it is the new man, regenerated in Christ Jesus, that is speaking. And even though the person of the Christian still sins, he assumes an altogether new and different attitude’ over against sin than does the unregenerated. It is true, he still sins. But at the same time, it is also evident that he hates the sin which he commits. And so it is true what the apostle Paul writes in: “Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.”