It is narrated from Ziyad bin Naeem Hadhrami, may Allah have mercy on him, that the Messenger of Allah, peace and blessings be upon him, said: "There are four things which Allah Almighty has made obligatory in Islam. If a servant performs three of them, they will not suffice him until he fulfills all of them. These four matters are: prayer, zakat, fasting in Ramadan, and pilgrimage to the House of Allah (Hajj)."