en_obs-tn/content/15/04.md

Then the priests must blow their trumpets

The connecting word Then introduces sequential action. The priests were to blow their trumpets after the Israelites had finished marching around the city seven times. (See: rc://en/ta/man/translate/grammar-connect-time-sequential)

must blow their trumpets

This could be translated as: “must sound their trumpets” or “must play their trumpets.” These trumpets were made out of ram’s horns.