Listen to the reason for his coming and glorify the power of the one who became flesh. The human race was deep in debt and incapable of paying what it owed. By the hand of Adam we all signed a bond to sin. The devil held us all in slavery. He kept producing our bills, using our suffering body as his paper. There he stood, the wicked forger, threatening us with our debts and demanding satisfaction. One of two things had to happen: either the penalty of death had to be imposed on all, because all had sinned (Rom. 3.23), or else a substitute had to be provided who was fully entitled to plead on our behalf. No man could save us; the debt would have been his liability too. No angel could buy us out, for such a ransom was beyond his powers. One who was sinless had to die for those who had sinned; that was the only way left by which to break the bonds of evil.
St. Proclus of Constantinople (+446), Homily on the Theotokos Delivered in the Presence of the Presbyter Nestorius
Fifth Century