It has already passed, in the chapter on Sayyiduna Ali's (may Allah be pleased with him) acceptance of Islam, that the Prophet (peace and blessings be upon him) said to Sayyidah Fatimah (may Allah be pleased with her): "Are you not pleased that your husband is the earliest of my Ummah in accepting Islam, the greatest of them in knowledge, and the foremost of them in forbearance?"
Ahmad and al-Tabarani recorded it through narrators who have been declared trustworthy.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب المناقب / 14669