(462) بَابُ التَّسْلِيمِ إِذَا جَاءَ الْمَجْلِسَ
Abu Hurayra reported that the Messenger of Allah, may Allah blesshim and grant him peace, said, "When one of you comes to a gathering, heshould give the greeting. If he leaves, he should give the greeting. Neitheris more of a duty than the other."
Reference: Al-Adab Al-Mufrad 1007
In-book reference: Book 42, Hadith 44
English translation: Book 42, Hadith 1007