שְֽׂפַת־אֱ֭מֶת תִּכּ֣וֹן לָעַ֑ד וְעַד־אַ֝רְגִּ֗יעָה לְשׁ֣וֹן שָֽׁקֶר׃
The lip of truth shall be established for ever; But a lying tongue is but for a moment.
Read kabbalistic (mystical) interpretation of Proverbs 12:19: and classical mystical sources.