From Sahih Muslim (Hadith 4907):
It has been narrated (through a still different chain of transmitters) on the authority of Abu Sa'id Khudrl that the Messenger of Allah (ﷺ) despatched a force to Banu Lihyan. (and said:) One man from every two should join the force. Then he said to those who stayed behind: Those of you who will look well after the family and wealth of those who are going on the expedition will be getting half the reward of the warriors
Reference: Muslim 4907