Ibn Abi Layla reported: Ka’b ibn Ujra met me and he said: Shall I not offer you guidance? The Messenger of Allah, peace and blessings be upon him, entered upon us and we said, “We know how to invoke peace upon you, but how do we invoke blessings upon you?” The Prophet said, “Say: O Allah, sanctify Muhammad and the family of Muhammad just as you have sanctified the family of Abraham. Verily, you are praiseworthy and glorious. O Allah, bless Muhammad and the family of Muhammad just as you have blessed the family of Abraham. Verily, you are praiseworthy and glorious.”

Source: Sahih Muslim 406

Grade: Sahih (authentic) according to Muslim

ابْنَ أَبِي لَيْلَى قَالَ لَقِيَنِي كَعْبُ بْنُ عُجْرَةَ فَقَالَ أَلَا أُهْدِي لَكَ هَدِيَّةً خَرَجَ عَلَيْنَا رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقُلْنَا قَدْ عَرَفْنَا كَيْفَ نُسَلِّمُ عَلَيْكَ فَكَيْفَ نُصَلِّي عَلَيْكَ 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

406 صحيح مسلم كتاب الصلاة باب الصلاة على النبي صلى الله عليه وسلم بعد التشهد