(464) بَابُ حَقِّ مَنْ سَلَّمَ إِذَا قَامَ
Abu Hurayra said, "Whoever meets his brother should greet him.If a tree or wall comes between them and then he meets him, he should greethim on the other side."
Reference: Al-Adab Al-Mufrad 1010
In-book reference: Book 42, Hadith 47
English translation: Book 42, Hadith 1010