Passages, indeed, might be found where corporeal and external (benefits) are improperly called “good,”— those things, viz., which contribute to the natural life, while those which do the reverse are termed “evil.” It is in this sense that Job says to his wife: “If we have received good at the hand of the Lord, shall we not also receive evil!” Since, then, there is found in the sacred Scriptures, in a certain passage, this statement put into the mouth of God, “I make peace, and create evil;” and again another, where it is said of Him that “evil came down from the Lord to the gate of Jerusalem, the noise of chariots and horsemen,” — passages which have disturbed many readers of Scripture, who are unable to see what Scripture means by “good” and “evil,”— it is probable that Celsus, being perplexed thereby, gave utterance to the question, “How is it that God created evil?” or, perhaps, having heard some one discussing the matters relating to it in an ignorant manner, he made this statement which we have noticed.
We, on the other hand, maintain that “evil,” or “wickedness,” and the actions which proceed from it, were not created by God. For if God created that which is really evil, how was it possible that the proclamation regarding (the last) judgment should be confidently announced, which informs us that the wicked are to be punished for their evil deeds in proportion to the amount of their wickedness, while those who have lived a virtuous life, or performed virtuous actions, will be in the enjoyment of blessedness, and will receive rewards from God?
I am well aware that those who would daringly assert that these evils were created by God will quote certain expressions of Scripture (in their support), because we are not able to show one consistent series of passages; for although Scripture (generally) blames the wicked and approves of the righteous, it nevertheless contains some statements which, although comparatively few in number, seem to disturb the minds of ignorant readers of holy Scripture. I have not, however, deemed it appropriate to my present treatise to quote on the present occasion those discordant statements, which are many in number, and their explanations, which would require a long array of proofs.
Evils, then, if those be meant which are properly so called, were not created by God; but some, although few in comparison with the order of the whole world, have resulted from His principal works, as there follow from the chief works of the carpenter such things as spiral shavings and sawdust, or as architects might appear to be the cause of the rubbish which lies around their buildings in the form of the filth which drops from the stones and the plaster.
Source: Against Celsus (New Advent)