The last two characteristics Paul lists here are both reiterations. He again denounces returning evil for evil, declaring, Never take your own revenge, beloved, but leave room for the wrath of God. If a wrong has been done to us, no matter how serious and harmful it may have been, we are never qualified for or have a right to render punishment for the offense ourselves. We are to leave that to the wrath of God. Quoting from the Mosaic law (Deuteronomy 32.35), the apostle reminds his readers that it is written, “Vengeance is Mine, I will repay,” says the Lord (cf. 2 Samuel 22.48; Nahum 1.2; Hebrews 10.30). In His divine time, the wrath of God will come (Colossians 3.6), and just retribution awaits the unforgiven.
From: The MacArthur New Testament Commentary: Romans 9-16 by John MacArthur (Chicago: Moody Publishers, 1994), p. 202. Comment at Romans 12.19. Emphasis in original.
John MacArthur turned 76 yesterday, January 19th. His commentary series, covering the entire New Testament, is now complete in 33 volumes (1983-2015).