And the Lord spake unto Moses,.... When the following directions concerning the trumpets were given is not certain; it may he at the time when the order of the camps of Israel was fixed, and is here recorded before the journeying of them, which was one use they were to be put unto, Numbers 10:2,
saying; as follows.

Here are directions concerning the public notices to be given the people by sound of trumpet. Their laws in every case were to be Divine, therefore, even in this matter Moses is directed. These trumpets typify the preached gospel. It sounds an alarm to sinners, calls them to repent, proclaims liberty to the captives and slaves of Satan, and collects the worshippers of God. It directs and encourages their heavenly journey; stirs them up to combat against the world and sin, encouraging them with the assurance of victory. It leads their attention to the sacrifice of Christ, and shows the Lord's presence for their protection. It is also necessary that the gospel trumpet give a distinct sound, according to the persons addressed, or the end proposed; whether to convince, humble, console, exhort, reprove, or teach. The sounding of the trumpet of the gospel is God's ordinance, and demands the attention of all to whom it is sent.

The Silver Signal-Trumpets. - Although God Himself appointed the time for removal and encampment by the movement of the cloud of His presence, signals were also requisite for ordering and conducting the march of so numerous a body, by means of which Moses, as commander-in-chief, might make known his commands to the different divisions of the camp. To this end God directed him to prepare two silver trumpets of beaten work (mikshah, see Exodus 25:18), which should serve "for the calling of the assembly, and for the breaking up of the camps," i.e., which were to be used for this purpose. The form of these trumpets is not further described. No doubt they were straight, not curved, as we may infer both from the representation of these trumpets on the triumphal arch of Titus at Rome, and also from the fact, that none but straight trumpets occur on the old Egyptian monuments (see my Arch. ii. p. 187). With regard to the use of them for calling the congregation, the following directions are given in Numbers 10:3, Numbers 10:4 : "When they shall blow with them (i.e., with both), the whole congregation (in all its representatives) shall assemble at the door of the tabernacle; if they blow with only one, the princes or heads of the families of Israel shall assemble together."