לְֽשׁוֹן־שֶׁ֭קֶר יִשְׂנָ֣א דַכָּ֑יו וּפֶ֥ה חָ֝לָ֗ק יַעֲשֶׂ֥ה מִדְחֶֽה׃
A lying tongue hateth those that are crushed by it; And a flattering mouth worketh ruin.
Read kabbalistic (mystical) interpretation of Proverbs 26:28: and classical mystical sources.