Sunan an-Nasai Book 13, Hadith 1291

أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعْدِ بْنِ إِبْرَاهِيمَ بْنِ سَعْدٍ، قَالَ حَدَّثَنَا عَمِّي، قَالَ حَدَّثَنَا شَرِيكٌ، عَنْ عُثْمَانَ بْنِ مَوْهَبٍ، عَنْ مُوسَى بْنِ طَلْحَةَ، عَنْ أَبِيهِ، أَنَّ رَجُلاً، أَتَى نَبِيَّ اللَّهِ صلى الله عليه وسلم فَقَالَ كَيْفَ نُصَلِّي عَلَيْكَ يَا نَبِيَّ اللَّهِ قَالَ ‏ "‏ قُولُوا اللَّهُمَّ صَلِّ عَلَى مُحَمَّدٍ وَعَلَى آلِ مُحَمَّدٍ كَمَا صَلَّيْتَ عَلَى إِبْرَاهِيمَ إِنَّكَ حَمِيدٌ مَجِيدٌ وَبَارِكْ عَلَى مُحَمَّدٍ وَعَلَى آلِ مُحَمَّدٍ كَمَا بَارَكْتَ عَلَى إِبْرَاهِيمَ إِنَّكَ حَمِيدٌ مَجِيدٌ ‏"‏ ‏.‏

It was narrated from Musa bin Talha, from his father, that:A man came to the Prophet of Allah (ﷺ) and said: "How should we send blessings upon you, O Prophet of Allah?' He said: 'Say: Alahumma salli 'ala Muhammad wa 'ala ali Muhammad, kama sallaita 'ala Ibrahima wa barik 'ala Muhammad kama barakta 'ala ali Ibrahim fil-'alamin, innaka hamidun majid (O Allah, send salah upon Muhammad and upon the family of Muhammad, as You sent salah upon the family of Ibrahim, and send blessings upon Muhammad and upon the family of Muhammad as You sent blessings upon the family of Ibrahim among the nations. You are indeed Worthy of praise, Full of glory)