Jeremiah 9:4-8

4Take ye heed every one of his friend, and confide not in any brother; for every brother only supplanteth, and every friend goeth about with slander.

5And they act deceitfully every one with his neighbour, and speak not the truth: they teach their tongue to speak falsehood, they weary themselves with perverse dealing.

6Thy habitation is in the midst of deceit; through deceit they refuse to know me, saith Jehovah.

7Therefore thus saith Jehovah of hosts: Behold, I will melt them, and try them; for how else could I do for the daughter of my people?

8Their tongue is a murderous arrow; it speaketh deceit. [A man] speaketh peaceably to his neighbour with his mouth, but in his heart he layeth his ambush.