Imam Malik's Muwatta, Chapter: Hajj

Yahya related to me from Malik from Nafi from Abdullah ibn Umar that the Messenger of Allah, may Allah bless him and grant him peace, entered the Kaba with Usama ibn Zayd, Bilal ibn Rabah and Uthman ibn Talha al-Hajabi and locked it behind him and stayed there for some time. Abdullah said that he asked Bilal when he came out what the Messenger of Allah had done there and he said, "He positioned himself with one support to his left, two supports to his right, and three behind him (the house had six supports at that time) and then he prayed."