Proverbs 10:18 KJV
He that hideth hatred with lying lips, and he that uttereth a slander, is a fool.
Proverbs 10:18, King James Version
In context
17 He is in the way of life that keepeth instruction: but he that refuseth reproof erreth.
18 He that hideth hatred with lying lips, and he that uttereth a slander, is a fool.
19 In the multitude of words there wanteth not sin: but he that refraineth his lips is wise.