Hadith 2474
Narrated Abdullah ibn Umar: Umar (may Allah be pleased with him) took a vow in the pre-Islamic days to spend a night or a day in devotion near the Kabah (in the sacred mosque). He asked the Prophet ﷺ about it. He said: Observe Itikaf (i. e. spend a night or a day near the Kabah) and fast.
Hadith 2475
Narrated Abdullah ibn Umar: The tradition mentioned above (No. 2468) has also been transmitted by Abdullah ibn Budayl through a different chain of narrators in a similar way. This version adds: While he (Umar) was observing Itikaf (in the sacred mosque), the people uttered (loudly): "Allah is most great. " He said: What is this, Abdullah? He said: These are the captives of the Hawazin whom the Messenger of Allah ﷺ has set free. He said: This slave-girl too? He sent her along with them.