Origen

“ But do not suppose that by nature, and from constitution, there are certain stumbling-blocks which seek out men through whom they come; for as God did not make death, so neither did He create stumbling-blocks; but free-will begot the stumbling-blocks in some who did not wish to endure toils for virtue. ”

“ And as it is necessary that that which is mortal should die, and it is impossible but that it should die, and as it must needs be that he who is in the body should be fed, for it is impossible for one who is not fed to live, so it is necessary and impossible but that occasions of stumbling should arise, since there is a necessity also that wickedness should exist before virtue in men, from which wickedness stumbling-blocks arise; for it is impossible that a man should be found altogether sinless, and who, without sin, has attained to virtue. ”

“ For the wickedness in the evil powers, which is the primal source of the wickedness among men, is altogether eager to work through certain instruments against the men in the world. And perhaps also the wicked powers are more exasperated when they are cast out by the word of Jesus, and their worship is lessened, their customary sacrifices not being offered unto them ”