Question: Among the common formulae of greeting the Prophet when visiting his grave are the following, “Al-Salaatu wa Al-Salaamu `alayka yaa rasool Allaah, i.e. Peace and blessings be upon you, O Messenger of Allaah” and “Allaahumma salli `Alaa Muhammad wa `alaa aali Muhammad, i.e. O Allaah, invoke blessings upon Muhammad and his family,” which of them is better?
Also, does the Prophet (peace be upon him) look at a person who greets him at his grave? Is it true that the Prophet (peace be upon him) waved a hand out of his grave to greet one of his honorable Sahaabah (Companions) or the pious people in return for their greetings?
Answer: (A) To the best of my knowledge, no certain formula of greeting the Prophet has been authentically reported from the Prophet (peace be upon him). Thus, both the formulae mentioned above are true… read more here.