This condensed statement of the whole doctrine of the incarnation is only the prologue to a historical treatise. The historical treatise which it introduces, naturally, is written from the point of view of its prologue.
Its object is to present Jesus Christ in His historical manifestation, as obviously the Son of God in flesh.
“These are written,” the Gospel testifies, “that ye may believe that Jesus is the Christ, the Son of God” (20:31); that Jesus who came as a man (1:30) was thoroughly known in His human origin (7:27), confessed Himself man (8:40), and died as a man dies (19:5), was, nevertheless, not only the Messiah, the Sent of God, the fulfiller of all the Divine promises of redemption, but also the very Son of God, that God only begotten, who, abiding in the bosom of the Father, is His sole adequate interpreter. From the beginning of the Gospel onward, this purpose is pursued: Jesus is pictured as ever, while truly man, yet manifesting Himself as equally truly God, until the veil which covered the eyes of His followers was wholly lifted, and He is greeted as both Lord and God (20:28).
But though it is the prime purpose of this Gospel to exhibit the Divinity of the man Jesus, no obscuration of His manhood is involved. It is the Deity of the man Jesus which is insisted on, but the true manhood of Jesus is as prominent in the representation as in any other portion of the New Testament. Nor is any effacement of the humiliation of His earthly life involved. For the Son of man to come from heaven was a descent (3:13), and the mission which He came to fulfil was a mission of contest and conflict, of suffering and death.
He brought His glory with Him (1:14), but the glory that was His on earth (17:22) was not all the glory which He had had with the Father before the world was, and to which, after His work was done, He should return (17:5). Here too the glory of the celestial is one and the glory of the terrestrial is another. In any event, John has no difficulty in presenting the life of Our Lord on earth as the life of God in flesh, and in insisting at once on the glory that belongs to Him as God and on the humiliation which is brought to Him by the flesh. It is distinctly a duplex life which he ascribes to Christ, and he attributes to Him without embarrassment all the powers and modes of activity appropriate on the one hand to Deity and on the other to sinless (Jn. 8:46; cf. 14:30; 1 Jn. 3:5) human nature. In a true sense his portrait of Our Lord is a dramatization of the God-man which he presents to our contemplation in his prologue.
— Benjamin B. Warfield
The Works of Benjamin B. Warfield, 2:194–195.