It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that once the Prophet (peace and blessings be upon him) said (while addressing us in a sermon): "O people! Hajj has been made obligatory upon you." Upon hearing this, Sayyiduna Aqra' bin Habis (may Allah be pleased with him) stood up and said: "O Messenger of Allah (peace and blessings be upon him)! Is Hajj obligatory every year?" The Prophet (peace and blessings be upon him) said: "If I had said yes, it would have become obligatory upon you every year, but if that had happened, you would not have been able to do it. Hajj is obligatory only once in a lifetime; whatever is more than that will be voluntary Hajj."