حَدَّثَنَا مُحَمَّدُ بْنُ يُوسُفَ، قَالَ: حَدَّثَنَا سُفْيَانُ، عَنْ هِشَامٍ، عَنِ الْحَسَنِ قَالَ: التَّسْلِيمُ تَطَوَّعٌ، وَالرَّدُّ فَرِيضَةٌ.
Al-Hasan said, "Greeting is an act of obedience while the answer is a duty."
Source: Al-Adab Al-Mufrad — repository translation · Imam Muhammad ibn Ismail al-Bukhari — authenticity/grade metadata requires independent source review · Sunnah.comAudio not available for the selected reciter.
Source: Al-Adab Al-Mufrad — repository arabic · Imam Muhammad ibn Ismail al-Bukhari · Sunnah.com