Messenger of Allah ﷺ said, "No child is born but has the Islamic Faith, but its parents turn it into a Jew or a Christian. It is as you help the animals give birth. Do you find among their offspring a mutilated one before you mutilate them yourself?" The people said, "O Messenger of Allah ﷺ! What do you think about those (of them) who die young?" The Prophet ﷺ said, "Allah knows what they would have done (were they to live)." (Using translation from Bukhārī 6599)
قَالَ رَسُولُ اللهِ ﷺ مَنْ يُولَدُ يُولَدُ عَلَى هَذِهِ الْفِطْرَةِ فَأَبَوَاهُ يُهَوِّدَانِهِ وَيُنَصِّرَانِهِ كَمَا تُنْتَجُ الْبَهِيمَةُ فَهَلْ تَجِدُونَ فِيهَا مِنْ جَدْعَاءَ حَتَّى تَكُونُوا أَنْتُمْ تَجْدَعُونَهَا؟ قَالُوا يَا رَسُولُ اللهِ أَفَرَأَيْتَ مَنْ يَمُوتُ وَهُوَ صَغِيرٌ؟ قَالَ اللهُ أَعْلَمُ بِمَا كَانُوا عَامِلِينَ