(475) بَابُ مَنْ لَمْ يَرُدَّ السَّلامَ
Al-Hasan said, "Greeting is an act of obedience while the answeris a duty." (ID)
Reference (ID): Al-Adab Al-Mufrad 1040 (ID)
In-book reference (ID): Book 42, Hadith 77 (ID)
English translation (ID): Book 42, Hadith 1040 (ID)