Rather, oppression (or extortions) maketh a wise man foolish; and a bribe etc. If a wise man, being in a high position, exercises oppression (see Psalms 62:10), or practices extortion, he becomes a fool in so doing. This verse is a warning against impatience in the exercise of power or the acquisition of riches.
Related Commentaries of Ecclesiastes 7:7
Ecclesiastes 7:7
7 Surely oppression maketh a wise man mad; and a gift destroyeth the heart.