Kaab bin Ujra met me and said, "Shall I give you a gift? The Prophet ﷺ came out to us, and we said, 'Messenger of Allah, we already know how to greet you with peace, but how should we send blessings upon you?'He replied, 'Say, O Allah, send blessings upon Muhammad and upon the family of Muhammad, as You sent blessings upon the family of Ibrahim. Indeed, You are Praiseworthy, Glorious. O Allah, bestow favor upon Muhammad and upon the family of Muhammad, as You bestowed favor upon the family of Ibrahim. Indeed, You are Praiseworthy, Glorious.'"
لقيني كعب بن عجرة فقال: ألا أهدي لك هدية؟ إن النبي ﷺ خرج علينا، فقلنا: يا رسول الله! قد علمنا كيف نسلم عليك، فكيف نصلي عليك؟ قال: فقولوا: اللهم صل على محمد، وعلى آل محمد، كما صليت على آل إبراهيم إنك حميد مجيد، اللهم بارك على محمد، وعلى آل محمد، كما باركت على آل إبراهيم، إنك حميد مجيد.
Bukhari narrated it in the Book of Supplications (6357), and Muslim in the Book of Prayer (406), both through the route of Shuba, who said, Hakam narrated to us, saying, I heard Abdul-Rahman bin Abu Layla, and he mentioned it.The sahih hadiths explicitly contain three wordings, "Ibrahim" alone, "the family of Ibrahim" alone, and the combination of both, "Ibrahim and his family," and this goes back to the narrators shortening or elaborating. This has already been mentioned in the Book of Supplications and Remembrances.