Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him), while leading the people in prayer, left out a verse. (After finishing the prayer) he said: "Which of you will correct me regarding my recitation?" Sayyiduna Ubayy said: "O Messenger of Allah, I will. You left out such-and-such a verse." He (peace and blessings be upon him) said: "I knew that if anyone could correct me, it would be you."
Ahmad recorded it, and its narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2353