From Abū Hurairah, may Allāh be pleased with him, who said: The Messenger of Allāh ﷺ said:

When one of you comes to a gathering, then let him give salām; then when he wants to get up [and leave it], let him give salām, for the first [salām] is not more deserving [of being said] than the last.

Ṣaḥīḥ Sunan Abī Dāwūd, 5208.