Sahih Muslim 1810
Sahih Muslim · Book 32: The Book of Jihad and Expeditions · Women participating in military expeditions with the men
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى ، أَخْبَرَنَا جَعْفَرُ بْنُ سُلَيْمَانَ ، عَنْ ثَابِتٍ ، عَنْ أَنَسِ بْنِ مَالِكٍ ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَغْزُو بِأُمِّ سُلَيْمٍ وَنِسْوَةٍ مِنَ الأَنْصَارِ مَعَهُ إِذَا غَزَا فَيَسْقِينَ الْمَاءَ وَيُدَاوِينَ الْجَرْحَى .
It has been narrated on the authority of Anas b. Malik who said that the Messenger of Allah (ﷺ) allowed Umm Sulaim and some other women of the Ansar to accompany him when he went to war; they would give water (to the soldiers) and would treat the wounded.