Sayyiduna Abdullah bin Umar (may Allah be pleased with them) narrates: Sayyiduna Umar (may Allah be pleased with him) said: O Messenger of Allah (peace and blessings of Allah be upon him)! May Allah send blessings upon you. In the days of ignorance, I made a vow that I would observe i'tikaf for one night in Masjid al-Haram. So the Prophet (peace and blessings of Allah be upon him) said: Fulfill your vow.
Hadith Referenceصحیح ابن حبان / كتاب النذور / 4380
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح: ق - انظر ما قبله.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرطهما