Sunan an-Nasa'i · Book 21 · Hadith 1949
أَخْبَرَنَا إِسْحَاقُ، قَالَ أَنْبَأَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ عَطَاءِ بْنِ يَزِيدَ اللَّيْثِيِّ، عَنْ أَبِي هُرَيْرَةَ، قَالَ سُئِلَ رَسُولُ اللَّهِ صلى الله عليه وسلم عَنْ أَوْلاَدِ الْمُشْرِكِينَ فَقَالَ " اللَّهُ أَعْلَمُ بِمَا كَانُوا عَامِلِينَ " .
It was narrated that Abu Hurairah said: "The Messenger of Allah (ﷺ) was asked about the children of the idolators and he said: 'Allah knows best what they would have done."'