"Every sin may Allāh forgive except for one who dies as a polytheist or a believer who intentionally kills a believer." It was recorded by Abū Dāwūd (4270), Ibn Ḥibbān (51), al-Ḥākim (4/351), and Ibn ʿAsākir in "Tārīkh Dimashq" (5/209/2) through the route of Khālid ibn Dihqān who said: We were in the expedition of Constantinople at (Dhalqiyyah) when a man from the people of Palestine, from their nobles and best, known for this, named Hāniʾ ibn Kulthūm ibn Sharīk al-Kinānī, came and greeted ʿAbd Allāh ibn Abī Zakariyyā, who recognized his due right. Khālid said to us: ʿAbd Allāh ibn Abī Zakariyyā narrated to us, saying: I heard Umm al-Dardāʾ say: I heard Abū al-Dardāʾ say: I heard the Messenger of Allāh (ṣallá Allāhu ʿalayhi wa-sallam) say: and he mentioned it. The context is from Abū Dāwūd, and al-Ḥākim said: "Its isnād is authentic," and al-Dhahabī agreed with him, and it is as they said, for all its narrators are trustworthy. The statement of the ḥāfiẓ regarding this Khālid: "Acceptable" is insufficient, for he is trustworthy, as Ibn Maʿīn and others have declared him trustworthy, as he himself mentioned in "al-Tahdhīb." The ḥadīth has a corroborating narration from Muʿāwiyah ibn Abī Sufyān, elevated. It was recorded by al-Nasāʾī (2/163), al-Ḥākim, and Aḥmad (4/99) through the route of Thawr from Abū ʿAwn from Abū Idrīs who said: I heard Muʿāwiyah giving a khuṭbah and he mentioned it. Al-Ḥākim said: "Its isnād is authentic." Al-Dhahabī agreed with him. I say: This Abū ʿAwn was not declared trustworthy by anyone other than Ibn Ḥibbān, and Ibn Abī Ḥātim translated him (4/414-415) without mentioning any criticism or endorsement