וַיַּכְשִׁיל֣וּהוּ עָלֵ֣ימוֹ לְשׁוֹנָ֑ם יִ֝תְנֹדֲד֗וּ כָּל־רֹ֥אֵה בָֽם׃
So they make their own tongue a stumbling unto themselves; all that see them shake the head.
Read Jewish philosophical commentary on Psalms 64:9: and classical philosophical sources.