Proverbs 26:23-26
23.Burning lips and a wicked heart are like a potsherd covered with silver dross.
24. He that hates disguises it with his lips, and lays up deceit within himself;
25. When he speaks graciously, believe him not: for there are seven abominations in his heart.

Psalms 55:21
The words of his mouth were smoother than butter, but war was in his heart: his words were softer than oil, yet were they drawn swords.