 The purpose of zakat is two-fold. One comes in hadith and one comes in an aya. One is to remove the quality of stinginess from the heart. And the other one is for a redistribution of wealth and a recognition that those who are poor aren't just poor because they haven't worked hard enough. The Prophet ﷺ says in a hadith, tell them that Allah has obligated on them sadaqah, to be taken from the rich amongst them and to be returned, meaning it wasn't actually theirs to begin with, to be returned to the poor amongst them.