The Book of Funerals
21/60. Chapter:
The Children Of The Idolaters
Sunan an-Nasai
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 was asked about the children of the idolators and he said: 'Allah knows best what they would have done."'
Reference : Sunan an-Nasa'i 1949In-book reference : Book 21, Hadith 132English translation : Vol. 3, Book 21, Hadith 1951