Majma al-Zawaid — Hadith 10183

Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) says: "Regard your own opinion as suspect in matters of religion!" Then he mentioned the whole hadith about al-Hudaybiyah, in which, further on, are these words: "When the Prophet (peace and blessings be upon him) had the agreement between himself and the people of Makkah written, he said: 'Write: Bismillah al-Rahman al-Rahim (In the name of Allah, the Most Gracious, the Most Merciful).' The disbelievers said: 'If we considered this to be right, we would have affirmed it; but write as it used to be written before: Bismika Allahumma (In Your name, O Allah).' The Prophet (peace and blessings be upon him) agreed to this, and I did not accept it, until the Prophet (peace and blessings be upon him) said to me: 'O Umar! You see that I have agreed, and you still refuse?' Sayyiduna Umar (may Allah be pleased with him) says: Then I agreed." (Allamah al-Haythami says:) I say: The hadith narrated from Sayyiduna Umar (may Allah be pleased with him) is mentioned in the "Sahih", but without this wording.
Al-Bazzar recorded it, and its narrators are the narrators of the Sahih.