Aswad binYazid narrated that 'Abdullah bin Mas'ud said:
"When yousendpeace and blessings upon the Messenger of Allah (ﷺ), then do itwell, for you do not know, that may be shown to him." They said tohim: "Teach us." He said: "Say: 'Allahumma aj'al salatakawa rahmatakawa barakatika 'ala sayyidil-mursalin waimamil-muttaqin wa khatamin-nabiyyin, Muhammad 'abdika wa Rasulikaimamil-khayri (wa qa'idil-khair), wa Rasulir-Rahmah.Allahummab'athhu maqaman mahmudanyaghbituhu bihil-awwalunawal-akhirun. Allahumma salli 'ala Muhammadinwa 'ala aliMuhammadin kama sallayta 'ala Ibrahim wa 'ala ali Ibrahim;Allahumma barik 'ala Muhammadin wa 'ala ali Muhammadin kamabarakta 'ala Ibrahim wa 'ala aliIbrahim, innakaHamidum Majid (O Allah, send Your grace, honour,mercy and blessingsupon the leader of the Messengers, the imam ofthe pious and the sealof the Prophets, Muhammad, Your slave andMessenger, the Imam of thegood (and the leader) of the good, and theMessenger of mercy. OAllah, raise him to a station of praise andglory that will be theenvy of the first and the last. O Allah, sendYour grace, honour andmercy upon Muhammad and upon the family ofMuhammad, as You sent Yourgrace, honour and mercy upon Ibrahim, Youare indeed Praiseworthy,Most Glorious. O Allah, send blessings uponMuhammad and upon thefamily of Muhammad as You sent blessings uponIbrahim and the familyof Ibrahim, You are Praiseworthy, MostGlorious).'"
English reference: Vol. 1, Book 5, Hadith 906
Arabic reference: Book 5, Hadith 959