Al-Kāfi

Hadith 2079
sexual-ethics
3- عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ النَّوْفَلِيِّ عَنِ السَّكُونِيِّ عَنْ أَبِي عَبْدِ اللهِ (عَلَيْهِ السَّلام) قَالَ قَالَ أَمِيرُ الْمُؤْمِنِينَ (عَلَيْهِ السَّلام) اللِّوَاطُ مَا دُونَ الدُّبُرِ وَالدُّبُرُ هُوَ الْكُفْرُ.
3. Ali ibn Ibrahim has narrated from his father from af-Nawfafiy from af-Sakuniy who has said the following: “Abu ‘Abd Allah (a.s.), has said that ’Amir al-Mu’minin has said, ‘Homosexuality is other than anal sex, anal sex is disbelief.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī