Risālat al-Ḥuqūq
Hadith 5وَأَمَّا حَقُّ السَّمْعِ فَتَنْزِيهُهُ عَنْ سَماع الغيبةِ و سَماعِها لا يحِلّ سَماعه.
The right of hearing is to keep it pure from listening to backbiting (ghiba) and listening to that to which it is unlawful to listen.