Repay no one evil for evil, but give thought to do what is honorable in the sight of all.
Romans 12:17

A fool gives full vent to his spirit, but a wise man quietly holds it back.
Proverbs 29:11

So don't bother correcting mockers; they will only hate you. But correct the wise, and they will love you.
Proverbs 9:8

Picking up a dog by the ears— that's what someone is like who meddles in another's fight.
Proverbs 26:17  

Gently instruct those who oppose the truth. Perhaps God will change those people's hearts, and they will learn the truth.
2 Timothy 2:25