كتاب الجهاد والسير
32  
The Book of Jihad and Expeditions
(48)
Chapter: Women who take part in military expeditions are to be given a reward but not a regular share; And the prohibition of killing children of the enemy
(48)
باب النِّسَاءُ الْغَازِيَاتُ يُرْضَخُ لَهُنَّ وَلاَ يُسْهَمُ وَالنَّهْىُ عَنْ قَتْلِ صِبْيَانِ أَهْلِ الْحَرْبِ
Sahih Muslim 1812 g

It has been narrated on the authority of Umm 'Atiyya, the Ansarite, who said:

I took part with the Messenger of Allah (ﷺ) in seven battles. I would stay behind in the camp of men, cook their food, treat the wounded and nurse the sick.
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَبْدُ الرَّحِيمِ بْنُ سُلَيْمَانَ، عَنْ هِشَامٍ، عَنْ حَفْصَةَ، بِنْتِ سِيرِينَ عَنْ أُمِّ عَطِيَّةَ الأَنْصَارِيَّةِ، قَالَتْ غَزَوْتُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم سَبْعَ غَزَوَاتٍ أَخْلُفُهُمْ فِي رِحَالِهِمْ فَأَصْنَعُ لَهُمُ الطَّعَامَ وَأُدَاوِي الْجَرْحَى وَأَقُومُ عَلَى الْمَرْضَى.
Reference : Sahih Muslim 1812g
In-book reference : Book 32, Hadith 172
USC-MSA web (English) reference : Book 19, Hadith 4462
  (deprecated numbering scheme)