“Allah sends His Salât (Graces, Honours, Blessings, Mercy) on the Prophet and also His angels (ask Allah to bless and forgive him).
O you who believe! Send your Salât on (ask Allah to bless him), and (you should) greet (salute) him with the Islamic way of greeting (salutation i.e. As¬Salâmu 'Alaikum)”
[AL-AHZAAB 33:56].