Sayyiduna Ibn Abbas (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) said: "O people! Hajj has been made obligatory upon you." It was asked: O Messenger of Allah! Is it obligatory every year? He replied: "No, and if I had said yes, it would have become obligatory every year. (Hajj) is obligatory only once in a lifetime, anything beyond that is voluntary."