It is narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him), he says: I was sitting in a gathering of the Ansar when Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) came to us, and he seemed somewhat frightened. In fact, Sayyiduna Umar (may Allah be pleased with him) had summoned him. So I went to him and sought permission three times, but when I was not granted permission, I turned back, because the Messenger of Allah (peace and blessings be upon him) said: Whoever seeks permission three times from someone and is not granted permission, then he should return. When I informed Sayyiduna Umar (may Allah be pleased with him) of this hadith, he said: Bring proof of this, otherwise I will punish you. So I came to seek testimony. Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) said: The youngest among us should stand with you for this. Sayyiduna Abu Sa'id (may Allah be pleased with him) said: I was the youngest, so I stood up and testified that the Messenger of Allah (peace and blessings be upon him) said: Whoever seeks permission three times and is not granted permission, then he should return.