Tertullian, Against Marcion 2.27

I will now settle the rest briefly. You gather up whatever petty, weak, and unworthy details you can find to tear down the Creator, but a simple, certain reason answers them all: God could not enter human life unless He took on human senses and affections, through which He could temper the force of His majesty — force utterly intolerable to human mediocrity — with humility. Such things are unworthy of God in themselves, yet necessary for man; that makes them worthy of God after all, because nothing is more worthy of God than human salvation. I would argue this at length if I were debating pagans — though the dispute with heretics is not much different — but since you already believe that God has walked among men in the form and full order of the human condition, your own faith should convince you that God conformed Himself to humanity. For if God, the more exalted One, has cast down the height of His majesty with such humility that He submitted even to death, and to death on a cross, why do you not think that some smallnesses were fitting for our God as well — smallnesses far more tolerable than the Jewish insults, crosses, and graves? Are these the smallnesses that should now prejudice Christ, subjected to human passions, into being the very God whose human weaknesses you reproach? We also confess that Christ always acted in the name of God the Father; He was conversing with the patriarchs and prophets from the beginning. He is the Son of the Creator, the Word of God, whom the Father brought forth from Himself and made His Son, placing Him over all His disposition and will, diminishing Him slightly below the angels, as it is written (Psalm 8:5; Hebrews 2:7). By this diminution the Father also appointed Him to the very things you condemn as merely human, learning already from the beginning what He would be in the end. He is the One who descended, the One who asked, the One who demanded, the One who swore. Moreover, because the Father has never been seen by anyone, the common Gospel itself testifies, with Christ saying: "No one has known the Father except the Son" (John 1:18; Matthew 11:27). For He had also declared in the Old Testament: "No one will see God and live" (Exodus 33:20), defining the invisible Father, in whose authority and name He Himself was the God who was seen as the Son of God. Among us, too, Christ is accepted in the person of Christ, because He is ours in that very way. Therefore, whatever you demand as worthy of God will be found in the invisible, unapproachable, peaceful Father — the philosophers' God, so to speak — but whatever you condemn as unworthy will be attributed to the Son, the One seen and heard and interacted with, the Father's arbiter and minister, blending in Himself man and God: God in virtues, man in smallnesses, so that He confers on man exactly as much as He detracts from God. Finally, the whole shame of my God, in your eyes, is the sacrament of human salvation. God conversed with men so that man might learn to act divinely. God acted on equal terms with man so that man might be able to act on equal terms with God. God was found small so that man might become great. You who disdain such a God do not know whether you believe in a crucified God by faith. How great, then, is your perversity toward both orders of the Creator? You despise Him as a judge, and you reproach the severity of the judge — severity congruent with the merits of the cases — as savagery; you demand a most excellent God. And you turn the leniency of His benignity — leniency congruent with the capacity of human mediocrity — into something worthless, so that you may depreciate the smallness. Neither the great nor the moderate pleases you, neither the judge nor the friend. What if the same things are now detected in your own God? We have already shown that He is a judge in His own book, and that a judge is necessarily severe, and that the severe one is certainly savage, if indeed He is savage.