The incarnation is one of the greatest events in time. The Son of God took manhood into His Person, forming a permanent union between His divine nature and His human nature. He became a man, spirit-soul-body, but did not give up anything He had as God.
“And the Word became flesh, and dwelt among us (and we have contemplated his glory, a glory as of an only-begotten with a father), full of grace and truth” (John 1:14)
He “dwelt among us”, visiting the human race in person, which is far different than the pre-incarnate appearances (theophanies) of the Son. Matt. 11:27 tells us that the Son’s identity is inscrutable to the human mind, only the Father can understand it. An infinite Being took on a finite form to reveal the infinite! However, when He took on manhood, He did so perfectly, and as man is a dependent order, the Son therefore made a decision to remain in the dependent place forever!
“…Christ Jesus; who, subsisting in the form of God, did not esteem it an object of rapine to be on an equality with God; but emptied himself, taking a bondman’s form, taking his place in the likeness of men” (Phil. 2:5-7)
Some would erroneously teach that Christ divested Himself of His deity in the incarnation. Col. 2:9 will quickly prove that to be a false interpretation. When it says He “emptied Himself” it refers to the veiling of His Godhead glory when He took on flesh. He veiled His personal glory such that it could not be seen by the human eye. However, by watching Him and contemplating Him, that glory could be observed by those who had faith (John 1:14).
But for the incarnation of the Son of God I should be ashamed to be a man.
— G.V. Wigram, September 27th, 1871
Pre-incarnate Appearances. Abraham saw "three men" in Genesis 18:2, but he recognized one of them as the Lord. Jehovah had come down to earth to visit Abraham in the form of a man. However, this was not incarnation. At the incarnation, "the Word became flesh, and dwelt among us" (John 1:14). In these pre-incarnate appearances, the Lord took on the physical form of a man, but it was only temporary. When the Word became flesh, it was permanent. Furthermore, at the incarnation, it wasn't merely a human body that the Son took, but manhood in all its attributes, apart from sin. The Son of God became a man: spirit, soul, and body. In Genesis 18 we see a body, but no soul or spirit. At the incarnation, the human and divine natures were joined in one inscrutable union, never to be dissolved! The pre-incarnate appearances are called theophanies. Several other examples include: Genesis 32:24-30; Judges 13:3-6; as well as references to "the Angel of Jehovah".