According to the consensus of classical Islamic scholarship, Zakat (الزكاة) is the third pillar of Islam, an obligatory annual charity that purifies a Muslim's wealth and soul. The Arabic root 'z-k-w' signifies purification, growth, and blessing, reflecting Zakat's dual function. As detailed by jurists like Al-Qurtubi, it is a precisely calculated amount, typically 2.5% of a person's surplus wealth held for a lunar year above a minimum threshold known as the 'nisab'. Its distribution is not arbitrary; the Quran, in Surah At-Tawbah (9:60), explicitly defines eight categories of recipients, ensuring it reaches the most vulnerable segments of society. Tafsir scholars like Ibn Kathir emphasize its spiritual dimension as an act of worship that cleanses one of greed and strengthens the community, with severe Quranic and Prophetic warnings for those who neglect it. Thus, Zakat is a foundational socio-economic institution in Islam, bridging personal devotion with communal social justice.