It was narrated that Ka'b bin 'Ujrah said:

"We said: 'O Messenger of Allah (ﷺ), we know about sending salams upon you, but how should we send salah upon you?' 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.)'" (One of the narrators) Ibn Abi Laila said: "We used to say: 'And also upon us.'" Abu Abdur-Rahman (An-Nasa'I) said: It was narrated from his book, and this is a mistake.

أَخْبَرَنَا الْقَاسِمُ بْنُ زَكَرِيَّا بْنِ دِينَارٍ، مِنْ كِتَابِهِ قَالَ حَدَّثَنَا حُسَيْنُ بْنُ عَلِيٍّ، عَنْ زَائِدَةَ، عَنْ سُلَيْمَانَ، عَنْ عَمْرِو بْنِ مُرَّةَ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي لَيْلَى، عَنْ كَعْبِ بْنِ عُجْرَةَ، قَالَ قُلْنَا يَا رَسُولَ اللَّهِ السَّلاَمُ عَلَيْكَ قَدْ عَرَفْنَاهُ فَكَيْفَ الصَّلاَةُ قَالَ ‏

‏ قُولُوا اللَّهُمَّ صَلِّ عَلَى مُحَمَّدٍ وَعَلَى آلِ مُحَمَّدٍ كَمَا صَلَّيْتَ عَلَى آلِ إِبْرَاهِيمَ إِنَّكَ حَمِيدٌ مَجِيدٌ اللَّهُمَّ بَارِكْ عَلَى مُحَمَّدٍ وَعَلَى آلِ مُحَمَّدٍ كَمَا بَارَكْتَ عَلَى آلِ إِبْرَاهِيمَ إِنَّكَ حَمِيدٌ مَجِيدٌ ‏

‏ ‏.‏ قَالَ ابْنُ أَبِي لَيْلَى وَنَحْنُ نَقُولُ وَعَلَيْنَا مَعَهُمْ ‏.‏ قَالَ أَبُو عَبْدِ الرَّحْمَنِ حَدَّثَنَا بِهِ مِنْ كِتَابِهِ وَهَذَا خَطَأٌ ‏.‏