חַיֵּ֣י בְ֭שָׂרִים לֵ֣ב מַרְפֵּ֑א וּרְקַ֖ב עֲצָמ֣וֹת קִנְאָֽה׃
A tranquil heart is the life of the flesh; But envy is the rottenness of the bones.
Read Kabbalistic (mystical) interpretations of Proverbs 14:30: Zohar and classical Jewish mystical sources, free online.