Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) narrates: The Prophet (peace and blessings of Allah be upon him) was leading us in prayer, and he began to recite a surah, but he omitted one verse from it. When he finished the prayer, I said: O Messenger of Allah! Has such-and-such verse been abrogated? The Prophet (peace and blessings of Allah be upon him) said: "No." I said: You did not recite it. The Prophet (peace and blessings of Allah be upon him) said: "Why did you not prompt me?"