Sahih al-Bukhari 6245

Ali ibn Abdullah narrated to us: Sufyan narrated to us: Yazid ibn Khusayfah narrated to us, from Busr ibn Said, from Abu Said al-Khudri, who said: I was in a gathering of the Ansar when Abu Musa came, seeming alarmed. He said, ‘I asked Umar for permission to enter three times, but I was not given permission, so I went back.’ Umar asked, ‘What prevented you?’ I said, ‘I asked permission three times, but was not given permission, so I went back. The Messenger of Allah, peace and blessings be upon him, said: When one of you asks permission three times and is not given permission, let him go back.’ Umar said, ‘By Allah, you must bring evidence for this. Is there anyone among you who heard it from the Prophet, peace and blessings be upon him?’ Ubayy ibn Kab said, ‘By Allah, only the youngest among the people will stand with you.’ I was the youngest, so I stood with him and informed Umar that the Prophet, peace and blessings be upon him, had said that. Ibn al-Mubarak said: Ibn Uyaynah informed me: Yazid told me, from Busr, who said: I heard Abu Said relate this same report.