ישעיהו נט:טו פירוש: רש״י ואבן עזרא

is considered mad Heb. מִשְׁתּוֹלֵל, considered mad by the people. Comp. (Micah 1:8) “I will go as a mad man (שׁוֹלָל).” This is equivalent to שׁוֹגֵג, inadvertent, which the Targum renders: שָׁלוּ. Likewise (II Sam. 6:7), “For his error (הַשַּׁל).”

משתולל According to some it means "mad;" comp. שולל "mad"¹³A. V., "stripped." (Mic. 1:8); אשתללו "they are mad" (Ps. 76::6); perhaps all these words are serived from שלל "to deprive of property;"¹⁴The meaning of משתולל accordingly is "maketh himself a prey (A. V.). משתולל is the participle Hitpael of שלל.

and was displeased for there is no justice Therefore, He brought retribution upon them.