“Do not be overcome by evil, but overcome evil with good.” (Romans 12:21)
Coming on the heels of the admonition not to take your own revenge, but to leave room for God’s wrath, this verse reminds us that there is more than one way of being “overcome with evil.” We might think of evil triumphing in the sense that the forces of evil might win some battle over those more righteous through military action, political victory, or social acceptance. But there are other ways that evil can “overcome.”
Evil can take ahold of our lives personally. It can fill us with hatred towards others, and to act towards them as they have acted towards us. Consequently we might actually “win” a battle, or a case, or a certain cause — but if we become consumed with anger and bitterness and hatred in the process, then in a very real sense, evil has “overcome” us, no matter how “good” the outcome was.
Thus the warning: “Do not be overcome by evil, but overcome evil with good.” That is why in some of the attendant verses here in Romans 12, God commands His people to respond to evil with directions like: “If you enemy is hungry, feed him …” etc. These kinds of actions help us to focus on God’s ultimate purpose for us, which is to become Christlike, and also make sure that we do not become angry, bitter, and “overcome by evil.”