Musnad Ahmad 179:24

Ya'la ibn 'Ubayd narrated to us, Muhammad—meaning Ibn Ishaq—narrated to us, from 'Asim ibn 'Umar, from Rafi' ibn Khadij, he said: I heard the Messenger of Allah, may Allah bless him and grant him peace, saying: "The one who works in [collecting] charity for the sake of Allah, the Almighty and Majestic, is like the warrior in the way of Allah until he returns to his family."