Lactantius — Divine Institutes 2.17

Someone will say: why then does God allow these things to happen and not rescue people from such bad errors? So that evils may fight with goods, so that vices may stand against virtues, so that he may have some to punish and others to honor.

For in the last times he has appointed to judge the living and the dead — of which judgment I will speak in the last book. So he delays until the end of times comes, when he will pour out his wrath in heavenly power and might, as the predictions of the pious prophets terrify with a dreadful warning.

For now he allows people to err and even to be impious against him — he himself being just and mild and patient. It cannot be that the one in whom there is perfect virtue should not also have perfect patience.