Wherefore not without cause has one of your own followers asked, "If God is, whence come evil things? If He is not, whence come good?"
Unde haud iniuria tuorum quidam familiarium quaesiuit: 'si quidem deus', inquit, 'est, unde mala? Bona uero unde, si non est?
Original text (Latin)
Notes from Wikiquote
Prose IV, line 30; translation by W.V. Cooper