904. Sunan Ibn Majah Chapter: The opening of the Prayer; Book 5, Hadith 102

It was
narrated that Hakam said: “I heard Ibn Abi Laila say: ‘Ka’b
bin
‘Ujrah met me and said: “Shall I not give you a gift? The
Messenger of Allah (ﷺ) came out to us and we said: ‘We know what
it
means to send greetings on you, but what does it mean to send
peace
and blessings upon you?’ He said: ‘Say: Allahumma salli
‘ala
Muhammadin wa ‘ala ali Muhammadin, kama sallayta ‘ala
Ibrahima, innaka
Hamidun Majid; Allahumma barik ‘ala Muhammadin wa
‘ala ali Muhammadin, kama barakta ‘ala Ibrahima,
innaka Hamidun Majid (O Allah, send your grace,
honour and mercy upon
Muhammad and upon the family of Muhammad, as
You sent Your grace,
honour and mercy upon Ibrahim, You are indeed
Praiseworthy, Most
Glorious. O Allah, send Your blessings upon
Muhammad and the family of
Muhammad, as You sent Your blessings upon
Ibrahim, You are indeed
Praiseworthy, Most Glorious).’”