Each trumpet was to be made of _one_ piece, and they fulfilled a double purpose. In other words, the source of the testimony was one, however the object and practical result might vary. Every movement in the camp was to be the result of the sound of the trumpet. Was the congregation to be gathered in festive joy and worship? it was by a certain sound of the trumpet. Were the tribes to be gathered in hostile array? it was by a blast of the trumpet. In a word, the solemn assembly and the warlike host, the instruments of music and the weapons of war,—all—all was regulated by the silver trumpet. Any movement, whether festive, religious, or hostile, that was not the result of that familiar sound, could be but the fruit of a restless and unsubdued will, which Jehovah could by no means sanction. The pilgrim host in the wilderness was as dependent upon the sound of the trumpet as upon the movement of the cloud. The testimony of God, communicated in that particular manner, was to govern every movement throughout the many thousands of Israel. Moreover, it pertained to the sons of Aaron, the priests, to blow with the trumpets, for the mind of God can only be known and communicated in priestly nearness and communion. It was the high and holy privilege of the priestly family to cluster around the sanctuary of God, there to catch the first movement of the cloud, and communicate the same to the most distant parts of the camp. They were responsible to give a certain sound, and every member of the militant host was equally responsible to yield a ready and an implicit obedience. It would have been at once positive rebellion for any to attempt to move without the word of command, or to refuse to move when once that word was given. All had to wait upon the divine testimony, and walk in the light thereof the very moment it was given. To move without the testimony would be to _move in the dark_; to refuse to move, when the testimony was given, would be _to remain in the dark_.