Answered by Shaykh Faraz Rabbani
The Impermissibility of Backbiting a Non-Muslim
Assalamu alaikum,
Imam al-Barkawi mentions in his al-Tariqa al-Muhammadiyya that backbiting (ghiba) is, “To mention the faults of your brother, if he is specified and known to the person addressed.”
Sayyidi Abd al-Ghani al-Nabulsi comments,
” the faults, ” that is, the blameworthy traits and shortcomings, or that which he dislikes.
“your brother,” in humanity, even if a non-believer (kafir)… it is stated in Tanwir al-Absar… that it is necessary to avoid hurting him, and it is impermissible (haram) to backbite him, just as a Muslim.
[Sayyidi Abd al-Ghani al-Nabulsi, al-Hadiqa al-Nadiyya Sharh al-Tariqa al-Muhammadiyya, 2: 218]
Wassalam,
Faraz Rabbani