Numbers 13:2

13:2 “Send out men to investigate the land of Canaan, which I am giving to the Israelites. You are to send one man from each ancestral tribe, each one a leader among them.”

Numbers 31:6

Campaign Against the Midianites

31:6 So Moses sent them to the war, one thousand from every tribe, with Phinehas son of Eleazar the priest, who was in charge of the holy articles and the signal trumpets.