Tertullian, Adversus Marcionem

10. But if you transfer the charge of wrongdoing from the man's account to the devil's, because it was he who incited the man to sin, and if you hope by this means to direct the blame against the Creator, as having created the devil--for, "He maketh angels spirits" [Ps 104:4] (I answer that) that which he was made by God, namely an angel, will be the responsibility of God who made him, while that which he was not made by God, namely the devil or accuser--it follows that he must have made himself that by bringing an accusation about God, a false one at that, first that God had forbidden them to eat of every tree, and next that if they did eat they would not die, and thirdly that God had selfishly denied them divinity. What then was the origin of this malice of lying and deceit directed against man and woman, and of the false accusation against God? Certainly it was not from God, for in common with all his works he had made that angel good. In fact until he became the devil he is declared the wisest of all: and I suppose the wisdom is no evil.

Also if you turn up Ezekiel's prophecy you will easily perceive that that angel was by creation good, and by his own act became corrupt. [Ezek 28:11-16] In the person of the prince of Tyre this pronouncement is made against the devil: "And the word of the Lord came unto me saying, Son of man, take up a lamentation upon the prince of Tyre and say, Thus saith the Lord, Thou art the unsealing of the likeness"--that is, thou hast unsealed (or annulled) the integrity of the image and likeness--"as a crown of beauty"--thus he speaks as to the most exalted of the angels, an archangel, the wisest of them all--"in the delights of the paradise of thy God thou wast born"--there, he means, where in the second creation, under the figure of animals ([cf. Gen 2:18-20], God made the angels.

"Thou wast clothed with the precious stone, the sardius, topaz, smaragdu, carbuncle, sapphire, jasper, lyncurium, agate, amethyst, chrysolite, beryl, onyx, and thou didst fill with gold thy storehouses and they treasuries. Since the day thou wast created I did set thee with the cherub in the holy mountain of God, thou wast in the midst of the stones of fire, thou wast irreproachable in thy days since the day thou wast created, until thine injuries were discovered. Of the multitude of thy merchandise thou hast filled thy garners, and hast sinned," and the rest, which it is evident properly apply to the castigation not of that particular prince but of an angel, because no one of mankind has ever been born in the paradise of God, not even Adam himself, for he was translated thither: nor had any man been set with the cherub in God's holy mountain, that is, in the height of heaven, from which our Lord testifies that Satan also fell: [Luke 10:18] nor has any man dwelt amid the stones of fire, among the gleaming rays of the burning constellations, from whence also Satan like lightning was cast down. Rather was he, the author of sin, being stigmatized in the person of a sinful man: aforetime irreproachable since the day of his creation, created by God for goodness, as by a good Creator of creatures without reproach: adorned with all angelic glory: set in God's presence, as good in the presence of the good, yet afterwards by himself transposed into evil. "Since the time, " he says, "that thy injuries were discovered," thus imputing to him those injuries by which he injured the man thrust out from God's obedience. He began to sin when he sowed the seed of sin, and so from then onwards was engaged in the "multitude of his merchandise," his wickedness, the full measure of his transgressions: for he also being a spirit, was no less (than the man) created with freedom of choice.

Anything so near to himself God cannot but have established in freedom of that sort. Yet by condemning him before (the final judgement ) God testified that through his own delight in wickedness voluntarily conceived he had turned aside from that pattern in which he was created: and by measuring out a set term to his activities God has put into effect the reason behind his own goodness, delaying the devil's extinction with the same intent and purpose with which he has deferred the restoration of man. He has allowed time for a contest, that the man might cast down his enemy by virtue of that same freedom of choice by which he had fallen before him, thus proving that the blame was not God's but his own, and by gaining the victory might honourably regain salvation. Thus the devil would suffer more bitter punishment, being overcome by him whom he had previously overthrown: and God would the more evidently be seen to be good, as he waited for the man to return back from (this present) life into paradise, now more glorious (than when driven out), with permission also to take and eat of the tree of life.