It is Allah Who knows what they would have done
حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا غُنْدَرٌ، حَدَّثَنَا شُعْبَةُ، عَنْ أَبِي بِشْرٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ سُئِلَ النَّبِيُّ صلى الله عليه وسلم عَنْ أَوْلاَدِ الْمُشْرِكِينَ فَقَالَ " اللَّهُ أَعْلَمُ بِمَا كَانُوا عَامِلِينَ ".
Narrated Ibn `Abbas: The Prophet (ﷺ) ; was asked about the offspring of the pagans. He said, "Allah knows what they would have done (were they to live).