Allah (The Glorified and the Exalted- Subhaanahu wa Ta’ala) commands in the Quran, “Take alms out of their property, you would cleanse them and purify them thereby, and pray for them; surely your prayer is a relief to them; and Allah is Hearing, Knowing.” [Al-Quran 9:103]
Narrated Ibn ‘Umar: Allah’s Apostle said: Islam is based on (the following) five (principles): To testify that none has the right to be worshipped but Allah and Muhammad is Allah’s Apostle; to offer the (compulsory congregational) prayers dutifully and perfectly; to pay Zakat (i.e. alms); to perform Hajj. (i.e. Pilgrimage to Mecca), and to observe fast during the month of Ramadan. (Al-Bukhari, Vol.1, Book 2, No.7).