Nothing Is So Worthy of God as Man's Salvation

For in him all the fullness of God was pleased to dwell, and through him to reconcile to himself all things, whether on earth or in heaven, making peace by the blood of his cross.  (Col 1:19-20)

God would have been unable to hold any intercourse with men, if He had not taken on Himself the emotions and affections of man, by means of which He could temper the strength of His majesty, which would no doubt have been incapable of endurance to the moderate capacity of man, by such a humiliation as was indeed degrading to Himself, but necessary for man, and such as on this very account became worthy of God, because nothing is so worthy of God as the salvation of man.… [Christ] means that the Father is invisible, in whose authority and in whose name was He God who appeared as the Son of God.  But with us Christ is received in the person of Christ, because even in this manner is He our God.  Whatever attributes therefore you require as worthy of God, must be found in the Father, who is invisible and unapproachable, and placid, and (so to speak) the God of the philosophers; whereas those qualities which you censure as unworthy must be supposed to be in the Son, who has been seen, and heard, and encountered, the Witness and Servant of the Father, uniting in Himself man and God, God in mighty deeds, in weak ones man, in order that He may give to man as much as He takes from God.

Tertullian, Against Marcion, 2.27