I came to the Prophet (ﷺ) and said: Upon you be peace, Messenger of Allah! He said: Do not say: Upon you be peace, for "Upon you be peace" is the salutation to the dead.
Sunan Abi Dawud Book 43, Hadith 437
← Previous Hadith The Prophet (ﷺ) said: When one of you comes to an assembly, he should give a salutation and if he feels inclined to get up, he should give a salutation, for the former is not more of a duty than the latter.

Sunan Abi Dawud Book 43, Hadith 436 Next Hadith → AbuDawud said: Al-Hasan ibn Ali traced this tradition back to the Prophet (ﷺ): When people are passing by, it is enough if one of them gives a salutation on their behalf, and that it is enough for those who are sitting if one of them replies.

Sunan Abi Dawud Book 43, Hadith 438