Some women requested the Prophet ﷺ to fix a day for them as the men were taking all his time. On that he promised them one day for religious lessons and commandments. Once during such a lesson the Prophet said, "A woman whose three children die will be shielded by them from the Hell fire." On that a woman asked, "If only two die?" He replied, "Even two (will shield her from the Hell-fire).  

قَالَتِ النِّسَاءُ لِلنَّبِيِّ ﷺ غَلَبَنَا عَلَيْكَ الرِّجَالُ فَاجْعَلْ لَنَا يَوْمًا مِنْ نَفْسِكَ فَوَعَدَهُنَّ يَوْمًا لَقِيَهُنَّ فِيهِ فَوَعَظَهُنَّ وَأَمَرَهُنَّ فَكَانَ فِيمَا قَالَ لَهُنَّ مَا مِنْكُنَّ امْرَأَةٌ تُقَدِّمُ ثَلاَثَةً مِنْ وَلَدِهَا إِلاَّ كَانَ لَهَا حِجَابًا مِنَ النَّارِ فَقَالَتِ امْرَأَةٌ وَاثْنَيْنِ فَقَالَ وَاثْنَيْنِ  

as above (the sub narrators are different). Abu Huraira qualified the three children referred to in the above mentioned Hadith as not having reached the age of committing sins (i.e. age of puberty) .  

عَنِ النَّبِيِّ ﷺ بِهَذَا وَعَنْ عَبْدِ الرَّحْمَنِ بْنِ الأَصْبَهَانِيِّ قَالَ سَمِعْتُ أَبَا حَازِمٍ عَنْ أَبِي هُرَيْرَةَ قَالَ ثَلاَثَةً لَمْ يَبْلُغُوا الْحِنْثَ