We used to go for Military expeditions along with Messenger of Allah ﷺ and provide the people with water, serve them and bring the dead and the wounded back to Medina.  

كُنَّا نَغْزُو مَعَ رَسُولِ اللَّهِ ﷺ نَسْقِي الْقَوْمَ وَنَخْدُمُهُمْ وَنَرُدُّ الْقَتْلَى وَالْجَرْحَى إِلَى الْمَدِينَةِ