It is narrated from Sayyiduna Ibn Umar, may Allah be pleased with them both, on the authority of Sayyiduna Umar, may Allah be pleased with him, that I once submitted in the presence of the Messenger of Allah, "O Messenger of Allah! I had vowed to observe i'tikaf for one night in Masjid al-Haram." The Prophet, peace and blessings be upon him, ordered him to fulfill that vow.