Theophylact of Ohrid — as excerpted in the Catena Aurea on John 1:14

“(in loc.) The Evangelist intends by making mention of the flesh, to shew the unspeakable condescension of God, and lead us to admire His compassion, in assuming for our salvation, what was so opposite and incongenial to His nature, as the flesh: for the soul has some propinquity to God. If the Word, however, was made flesh, and assumed not at the same time a human soul, our souls, it would follow, would not be yet restored: for what He did not assume, He could not sanctify. What a mockery then, when the soul first sinned, to assume and sanctify the flesh only, leaving the weakest part untouched! This text overthrows Nestorius, who asserted that it was not the very Word, even God, Who the Self-same was made man, being conceived of the sacred blood of the Virgin: but that the Virgin brought forth a man endowed with every kind of virtue, and that the Word of God was united to him: thus making out two sons, one born of the Virgin, i. e. man, the other born of God, that is, the Son of God, united to that man by grace, and relation, and lover. In opposition to him the Evangelist declares, that the very Word was made Man, not that the Word fixing upon a righteous man united Himself to him.”