It is narrated from Sayyiduna Abdur Rahman bin Abzi that the Noble Prophet (peace and blessings be upon him) led the Fajr prayer and left out a verse. When he finished the prayer, he asked: "Is Ubayy bin Ka'b among the people?" Sayyiduna Ubayy said: "O Messenger of Allah! Has such-and-such verse been abrogated or did you forget it?" The Prophet (peace and blessings be upon him) said: "I forgot it."