Only the priests, Aaron’s descendants, are allowed to blow the trumpets. This is a permanent law for you, to be observed from generation to generation.
Shebaniah, Joshaphat, Nethanel, Amasai, Zechariah, Benaiah, and Eliezer—all of whom were priests—were chosen to blow the trumpets as they marched in front of the Ark of God. Obed-edom and Jehiah were chosen to guard the Ark.
Then Moses sent them out, 1,000 men from each tribe, and Phinehas son of Eleazar the priest led them into battle. They carried along the holy objects of the sanctuary and the trumpets for sounding the charge.