What is the ruling on saying: "Upon you be peace, O Messenger of Allah, may Allah bless him and grant him peace" while praising the Prophet, may Allah bless him and grant him peace, and what is its evidence?

One who uses the second-person pronoun (you) in praising the Prophet, peace and blessings be upon him, falls into one of two categories: The first is that he believes the Prophet's spirit, peace and blessings be upon him, is present in the gathering and is being addressed. This is an innovation (bid'ah) and a reprehensible act (munkar). The second is that he addresses him metaphorically and by recalling his noble self. There is no harm in this, as in the Tashahhud: "Peace be upon you, O Prophet."

The praiser's statement: "Peace be upon you, O Messenger of Allah," falls under this category. If he believes the Prophet, peace and blessings be upon him, is present and returning the salutation, then this is ignorance and superstition. However, if he intends to recall the Prophet, peace and blessings be upon him, and address him, then there is no harm in it. It does not contradict the prohibition of saying "Peace be upon you" to a living person, because the Prophet, peace and blessings be upon him, has passed away, and addressing the deceased in this manner is not forbidden; it is purely a supplication.