Augustine of Hippo — as excerpted in the Catena Aurea on Matthew 5:38-42

“(Serm. in Mont. i. 20.) Whence the Lord judges that others’ weakness should rather be borne with compassion, than that our own should be soothed by others’ pain. For that retribution which tends to correction is not here forbidden, for such is indeed a part of mercy; nor does such intention hinder that he, who seeks to correct another, is not at the same time ready himself to take more at his hands. But it is required that he should inflict the punishment to whom the power is given by the course of things, and with such a mind as the father has to a child in correcting him whom it is impossible he should hate. And holy men have punished some sins with death, in order that a wholesome fear might be struck into the living, and so that not his death, but the likelihood of increase of his sin had he lived, was the hurt of the criminal. Thus Elias punished many with death, and when the disciples would take example from him they were rebuked by the Lord, who did not censure this example of the Prophet, but their ignorant use of it, seeing them to desire the punishment not for correction’s sake, but from angry hate. But after He had inculcated love of their neighbour, and had given them the Holy Spirit, there wanted not instances of such vengeance; as Ananias and his wife who fell down dead at the words of Peter, and the Apostle Paul delivered some to Satan for the destruction of the flesh. Yet do some, with a kind of blind opposition, rage against the temporal punishments of the Old Testament, not knowing with what mind they were inflicted.”