Sahih Muslim — The Book of Destiny — Hadith No: 6766
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا أَبُو عَوَانَةَ، عَنْ أَبِي بِشْرٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، قَالَ سُئِلَ رَسُولُ اللَّهِ صلى الله عليه وسلم عَنْ أَطْفَالِ الْمُشْرِكِينَ قَالَ " اللَّهُ أَعْلَمُ بِمَا كَانُوا عَامِلِينَ إِذْ خَلَقَهُمْ " .
Translation
Ibn Abbas reported that Allah's Messenger (ﷺ) was asked about the children of the polytheists, whereupon he said:It is Allah alone Who knows what they would be doing according to their creation