Sahih al-Bukhari — Merits of the Helpers in Madinah (Ansaar) — Hadith No: 3830
Translation
Narrated `Amr bin Dinar and 'Ubaidullah bin Abi Yazid:In the lifetime of the Prophet (ﷺ) there was no wall around the Ka`ba and the people used to pray around the Ka`ba till `Umar became the Caliph and he built the wall around it. 'Ubaidullah further said, "Its wall was low, so Ibn Az-Zubair built it