Musnad Ahmad 1173:3

Bishr ibn al-Mufaddal narrated to us, from Khalid ibn Dhakwan, from al-Rubayyi' bint Mu'awwidh ibn 'Afra', who said: "We used to go on military expeditions with the Messenger of Allah, may Allah bless him and grant him peace. We would give the people water to drink, serve them, and transport the wounded and the killed back to Medina."