Zakat is the third pillar of Islam that involves mandatory charity. It is mentioned frequently in the Quran and details were further revealed through the Prophet Muhammad. Zakat purifies wealth and souls, and is a form of worship that benefits both the giver and recipients. It must be paid annually on certain categories of wealth that meet the minimum threshold, known as nisab, which varies based on asset type. Zakat can only be given to specific groups of eligible poor and needy people, as well as those employed to collect it.