Sahih al-Bukhari, Book 82, Hadith 5 (In-Book) ⓘ
Narrated Abu Huraira: Allah's Messenger was asked about the offspring of the pagans. He said, "Allah knows what they would have done (were they to live)."
حَدَّثَنَا يَحْيَى بْنُ بُكَيْرٍ، حَدَّثَنَا اللَّيْثُ، عَنْ يُونُسَ، عَنِ ابْنِ شِهَابٍ، قَالَ وَأَخْبَرَنِي عَطَاءُ بْنُ يَزِيدَ، أَنَّهُ سَمِعَ أَبَا هُرَيْرَةَ، يَقُولُ سُئِلَ رَسُولُ اللَّهِ صلى الله عليه وسلم عَنْ ذَرَارِيِّ الْمُشْرِكِينَ فَقَالَ {اللَّهُ أَعْلَمُ بِمَا كَانُوا عَامِلِينَ }
also referenced under: Hadith 6598 (DarusSalam) & Volume 8, Book 77, Hadith 597 (USC-MSA)