The seven priests bearing the seven trumpets of rams' horns before the ark of Yahweh went on continually, and blew the trumpets: and the armed men went before them; and the rearward came after the ark of Yahweh, [the priests] blowing the trumpets as they went.
"The first time that we read of a trumpet-blast is at Sinai, where the Lord announced His descent upon the mount to the people assembled at the foot to receive Him, not only by other fearful phenomena, but also by a loud and long-continued trumpet-blast (Ex. xix. 16, 19, xx. 14 (18). After this we find the blowing of trumpets prescribed as part of the Israelitish worship in connection with the observance of the seventh new moon’s day (Lev. xxiii. 24), and at the proclamation of the great year of jubilee (Lev. xxv. 9). Just as the trumpet-blast heard by the people when the covenant was made at Sinai was as it were a herald’s call, announcing to the tribes of Israel the arrival of the Lord their God to complete His covenant and establish His kingdom upon earth; so the blowing of trumpets in connection with the round of feasts was intended partly to bring the people into remembrance before the Lord year by year at the commencement of the sabbatical month, that He might come to them and grant them the Sabbath rest of His kingdom, and partly at the end of every seven times seven years to announce on the great day of atonement the coming of the great year of grace and freedom, which was to bring to the people of God deliverance from bondage, return to their own possessions, and deliverance from the bitter labours of this earth, and to give them a foretaste of the blessed and glorious liberty to which the children of God would attain at the return of the Lord to perfect His kingdom (vid. Pentateuch, vol. ii, p. 466-7). But when the Lord comes to found, to build up, and to perfect His kingdom upon earth, He also comes to overthrow and destroy the worldly power which opposes His kingdom. The revelation of the grace and mercy of God to His children, goes ever side by side with the revelation of justice and judgment towards the ungodly who are His foes. If therefore the blast of trumpets was the signal to the congregation of Israel of the gracious arrival of the Lord its God to enter into fellowship with it, no less did it proclaim the advent of judgment to an ungodly world." [Note: Keil and Delitzsch, pp. 69-70.] 