Proverbs 20:22
Say not thou, I will recompense evil; but wait on the Lord, and He shall save thee.

But what about when people speak badly about us, and what they say isn't true? Surely then we can do the same thing? Surely the Lord would want us to defend ourselves and set the person right? Not so. Proverbs 20:3 says It is an honor for a man to cease from strife.
If we answer harsh words with equally harsh words, we are creating strife. If we choose instead to smile and walk away, praying for the person, we are responding correctly. If we do that, we have done our best to show God's love.
Is it easy? Not at all - the human reaction is to get defensive and respond in kind. Let us strive to give a response that will bring glory to our Lord and be a good testimony to others.

Isaiah 25:1
O Lord, Thou art my God; I will exalt Thee, I will praise Thy Name; for Thou hast done wonderful things; Thy counsels of old are faithfulness and truth.

Have a blessed Sunday!