Sunan Abi Dawud, Hadith 4694

Ibn ‘Abbas reported that when the Prophet (May peace be upon him) was questioned about the offspring of polytheists, he said : Allah knows best about what they were doing.

حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ أَبِي بِشْرٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم سُئِلَ عَنْ أَوْلاَدِ الْمُشْرِكِينَ فَقَالَ ‏ "‏ اللَّهُ أَعْلَمُ بِمَا كَانُوا عَامِلِينَ ‏" ‏ ‏.‏

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also referenced under: Hadith 4711 (DarusSalam)