How was Jesus fully God and fully man?

Here, then, we are confronted with the unfathomable mystery of the person and being of the Lord Jesus Christ as uniting in Himself both Godhead and humanity. As God, life is as essentially His own—as eternal and self-existent in Him, as in the Father Himself (John 1:4); but as to His humanity, born in time, the privilege of having life in Himself as it is in the Father, is a derived result of that mysterious union into which the humanity of the Lord has been taken with His divinity. That life which is proper to God dwells as fully in the incarnate Son as in the Godhead itself, according to that other Scripture (Col. 2:9), which declares that "in Him dwells all the fulness of the Godhead bodily."

Scripture never divides His Person into two parts, one human and one divine, but reveals Him as having taken up perfect humanity into union with His eternal deity so that they are united in one unique, inscrutable and indissoluble bond in His Person. While Scripture never confounds the two natures it never divides the Person. Even what He does in manhood is still the action of Himself, the eternal Son, who has of His own self, and without giving up His personality as eternal Son, "taking a bondman's form, taking His place in the likeness of men" (Phil. 2:7, J. N. D. Trans.). It is He the eternal Son that is there as Man. It is this fact of His Person as the eternal Son of God, having taken His place as Man, that gives the infinite perfection of His unique Person to all that He does as incarnate Son. It is this indissoluble union of perfect manhood with eternal deity in His unique Person that constantly comes out in all that He does as God (the Son) manifest in flesh.

He took up humanity into union with deity in His Person; yet His incarnation did not in the least detract from His deity nor His eternal relationship as Son to the Father but only gave to His humanity His infinite perfection. Each of His two natures retained its own proper character without any confusion. His human nature as well as His divine nature possessed each their excellent characteristics and both united to form His glorious Person as incarnate Son. Scripture never divides the Person nor confounds the natures. They are united in His Person by a unique and inscrutable bond. He is the God-man He is God in all that God is and He is Man in all that man is, apart from sin. Such is the Son of God come in flesh — the God-man — that He might manifest the Godhead in the flesh and by His obedience unto death, even the death of the cross, might redeem us unto God.

There are, then, two sides to the person of Christ. He was God manifest in flesh. "The Word was made flesh and dwelt among us (and we beheld His glory, the glory as of the only begotten of the Father,) full of grace and truth" (John 1:14). The Word was the Eternal Son, and the Eternal Son became man. He was thus God and man — a union of extremes which was not possible in any other, and rendering His person so unfathomable, so incomprehensible, that He Himself said, "No man knows the Son but the Father" (Matt. 11:27). But it is essential that we hold fast both His true Divinity and His as equally true humanity. For had He not been true man, He could not have been a sacrifice for sin, and had He not been God, His sacrifice could not have been available for all. Satan knows this, and hence, in every age, he has sought to undermine the one or the other of these truths, insinuating doubts sometimes concerning His humanity and sometimes concerning His Divinity. But it is the glory of the person of Christ that He is both Divine and human, that He is, in His one person, both God and man. This truth lies at the foundation of, and, indeed, gives its character to, redemption.

The opposite error to saying that He is two persons is to say that His two natures have combined into one. It was an ancient heresy that the two natures, Manhood and Deity, merged together. For this reason the writer does not like the expression the “God-man”. It implies to him (though not to many orthodox Christians) that He is half man and half God. Such an idea must be resisted. He is wholly Man and wholly God. He possesses all the attributes and properties of real, unfallen, holy Manhood, and at the same time possesses all the infinite attributes and properties of Deity. The unity consists, not in the amalgamation of essence, but in the Oneness of His Person.

It is not merely that He was manifested in the body, that He had a human form, nor that He had a human intellect as well — perfect, imperial, human intellect; but He had also human affection. In other words, in body, soul and spirit He was as absolutely and entirely a man as He was absolutely and entirely God also. Faith must always be careful, first of all, to hold the entire truth, to receive everything that God reveals, and then let the Spirit of God harmonize what may apparently seem a contradiction. The great error into which men fall is that of shutting out a part of God's truth. The way to have the light is to welcome it all. Leave the Spirit of God to harmonize that which our poor, finite minds may but feebly grasp. We may be sure that it is all perfectly consistent with the divine glory. Our care is to receive it all.

The incarnation is a profound mystery. The mind of man cannot explain it or understand how it was effected, but the fact is plainly evident. The power of the Holy Spirit in and through the virgin produced a Man who is both a divine and a human Person. Thus supernaturally come into the world, He unites Deity and humanity in Himself — in one Person. He is thus truly God and truly Man: with human spirit, soul and body — God is seen in flesh.

This is a great mystery, and all the historic fundamental errors concerning His Person have been attempts to explain it in some measure. It is inexplicable. He is a real Man and true God in One Person. The two natures, manhood and Deity, are not joined together to form one nature, but are united in One Person. They ever remain distinct but are never separated. Their union is personal, not consubstantial.

We can and must believe the great facts of the twofold nature of our adorable Lord and Master. They are stated clearly in God’s Word. He is very God, He is very man, yet one Person. No wonder the Apostle Paul could burst forth, “Great is the mystery of godliness: God was manifest in the flesh” (1 Tim. 3:16).

The blessed Lord in assuming manhood took all that was necessary for manhood, spirit, soul, and body; the spirit of a man, the soul of a man, the body of a man—in other words a human spirit, a human soul, a human body—full complete manhood. And yet, united to Deity there was but one indivisible Person. Such is the teaching of Scripture, such the mystery that our Lord declares none can know but the Father.