The alternative to revenge
To the contrary, “if your enemy is hungry, feed him; if he is thirsty, give him something to drink; for by so doing you will heap burning coals on his head.” Do not be overcome by evil, but overcome evil with good. – Romans 12:20-21
So, the answer to being persecuted and wronged is to feed our enemy, give them something to drink, or in other words, show love to them. Paul, here, is quoting Proverbs, and this Proverb is the solution to evil.
What happens, then, is that Christian will heap burning coals on his head. Some think that this means that the evildoer will be brought to repentance. But it should be noted that burning coals in Scripture is always associated with punishment. So, the kindness done to evil doers is actually their punishment.
When someone wrongs another and is wronged back, they feel vindicated. But when someone wrongs another and is shown grace and mercy, that is piercing to the heart, and carries in itself a punishment of conscience. We use the term today, “Kill ’em with kindness.” That is the biblical principle here.
God, when He was sinned against by His creation, did not repay evil for evil, but instead gave His only Son to die on the cross so that everyone who believes in Him would not face His wrath but be saved. And God’s kindness is meant to lead you to repentance (2:4). Our kindness in the midst of being wronged is a picture of this gospel.
So, Christian, do not avenge yourselves, but show kindness. Our kindness is God’s temporal judgment on them and perhaps a means to show them Jesus. And it is our act of worship to the King.