It is narrated on the authority of 'Abdullah that a woman was found killed in one of the battles fought by the Messenger of Allah ﷺ. He disapproved of the killing of women and children.  

أَنَّ امْرَأَةً وُجِدَتْ فِي بَعْضِ مَغَازِي رَسُولِ اللَّهِ ﷺ مَقْتُولَةً فَأَنْكَرَ رَسُولُ اللَّهِ ﷺ قَتْلَ النِّسَاءِ وَالصِّبْيَانِ  

It is narrated by Ibn 'Umar that a woman was found killed in one of these battles; so the Messenger of Allah ﷺ forbade the killing of women and children.  

وُجِدَتِ امْرَأَةٌ مَقْتُولَةً فِي بَعْضِ تِلْكَ الْمَغَازِي فَنَهَى رَسُولُ اللَّهِ ﷺ عَنْ قَتْلِ النِّسَاءِ وَالصِّبْيَانِ