John Calvin's Commentary on the Bible - Romans 12:17
Verse 17 17.Repaying to no one, etc. This differs but little from what shortly after follows, except that revenge is more than the kind of repaying of which he speaks here; for we render evil for evil sometimes, even when we exact not the requiting of an injury, as when we treat unkindly those who do us no good. We are indeed wont to form an estimate of the deserts of each, or of what they merit at our hands, so that we may confer our benefits on those, by whom we have been already obliged, or... read more
Adam Clarke's Commentary on the Bible - Romans 12:21
Be not overcome of evil - Do not, by giving place to evil, become precisely the same character which thou condemnest in another. Overcome evil with good - however frequently he may grieve and injure thee, always repay him with kindness; thy good-will, in the end, may overcome his evil. Thomas Aquinas has properly said: Vincitur a malo qui vult peccare in alium, quia ille peccavit in ipsum . "He is overcome of evil who sins against another, because he sins against him." A moral enemy is... read more