Tertullian

“ For He afforded room for a conflict, wherein man might crush his enemy with the same freedom of his will as had made him succumb to him (proving that the fault was all his own, not God’s) , and so worthily recover his salvation by a victory; wherein also the devil might receive a more bitter punishment, through being vanquished by him whom he had previously injured; and wherein God might be discovered to be so much the more good, as waiting [12] for man to return from his present life to a more glorious paradise, with a right to pluck of the tree of life. ”

“ From the day when thou wast created, when I set thee, a cherub, upon the holy mountain of God, thou wast in the midst of stones of fire, thou wast irreproachable in thy days, from the day of thy creation, until thine iniquities were discovered. ”

“ The Devilish Nature Superadded by Wilfulness. In Man’s Recovery the Devil is Vanquished in a Conflict on His Own Ground.
If, however, you choose to transfer the account [1] of evil from man to the devil as the instigator of sin, and in this way, too, throw the blame on the Creator, inasmuch as He created the devil,—for He maketh those spiritual beings, the angels—then it will follow that [2] what was made, that is to say, the angel, will belong to Him who made it; while that which was not made by God, even the devil, or accuser, [3] cannot but have been made by itself ”