ה֣וֹן עָ֭שִׁיר קִרְיַ֣ת עֻזּ֑וֹ מְחִתַּ֖ת דַּלִּ֣ים רֵישָֽׁם׃
富人的財富是他的堅固城；窮人的貧乏是他們的敗壞。
Ibn Ezra
The rich man's wealth is like a fortress that will save him from moments of troubles even though he is not wise; and “the poor” i.e., the heartless, their poverty will ruin them.
Rashi
the destruction of the poor is their poverty The poverty that they did not engage in the Torah is their destruction.