Gregory the Great — as excerpted in the Catena Aurea on Matthew 25:46

“(ubi sup.) But they say, no just man takes pleasure in cruelties, and the guilty servant was scourged to correct his fault. But when the wicked are given over to hell fire, to what purpose shall they burn there for ever? We reply, that Almighty God, seeing He is good, does not delight in the torments of the wretched; but forasmuch as He is righteous, He ceases not from taking vengeance on the wicked; yet do the wicked burn not without some purpose, namely, that the righteous may acknowledge how they are debtors for eternity to Divine grace, when they see the wicked suffering for eternity misery, which themselves have escaped only by the assistance of that Divine grace.”