“See that none render evil for evil unto any man; but ever follow that which is good, both among yourselves, and to all men.”  
1 Thessalonians 5:15

So apt- don’t render evil for evil unto ANY man- believer or unbeliever. Don’t pay back and don’t ask God or your special angels to pay back anyone evil; a simple instruction you would do well to keep.
He said instead ever follow that which is good, among the brethren and unbelievers. This is amazing; so even when you have every right to be offended by that unbeliever, he says ever follow that which is good, meaning there’s something good to look out for- at least you know the most important thought; If Jesus died for them, there must be something special about them.
No matter what evil you have had to endure, God says:
“Rejoice evermore.”  1 Thessalonians 5:16
He emphasizes:
“Not rendering evil for evil, or railing for railing: but contrariwise blessing; knowing that ye are thereunto called, that ye should inherit a blessing.”  1 Peter 3:9
Don’t try to render evil for evil because you should know that your calling is to inherit a blessing, so even if someone did something to you and meant it for evil, you are ordained to inherit a blessing out of that seeming evil situation:
“But as for you, ye thought evil against me; but God meant it unto good…”  Genesis 50:20