Proverbs 30:10

10 “Do not slander a servant to their master, or they will curse you, and you will pay for it.

Read Proverbs 30:10 Using Other Translations

Accuse not a servant unto his master, lest he curse thee, and thou be found guilty.
Do not slander a servant to his master, lest he curse you, and you be held guilty.
Never slander a worker to the employer, or the person will curse you, and you will pay for it.