Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Abdur Rahman bin Abi Laila that a man came to Hazrat Ka'b bin Ujrah (may Allah be pleased with him) and began to mention what had been revealed in the Qur'an about Abdullah bin Ubayy and started to speak ill of him. There was also a relationship of respect and kinship between the two. Hazrat Ka'b (may Allah be pleased with him) listened silently. After that, the man went to Hazrat Umar (may Allah be pleased with him) and said, "O Commander of the Faithful, shall I tell you that I mentioned before Ka'b what has been revealed in the Qur'an about Abdullah bin Ubayy, but he showed no reaction to it." After that, Hazrat Umar (may Allah be pleased with him) met Hazrat Ka'b (may Allah be pleased with him) and said, "I have been informed that Abdullah bin Ubayy was mentioned before you, and you showed no reaction?" Hazrat Ka'b (may Allah be pleased with him) replied, "I heard what he said, but when I saw that he deliberately wanted to find fault with me, I thought it inappropriate to help him in finding fault with myself." Hazrat Umar (may Allah be pleased with him) said, "It would have been better if you had struck him on the nose," or he said, "It would have been better if you had broken his nose."