Kommentar zu Bamidbar 10:2

עשה לך MAKE THEE etc. — make לך, “for thyself” (on thy own behalf) suggests that they shall blow them in your presence, as before a king, as it is said, (with reference to Moses) (Deuteronomy 33:5) ויהי בישרון מלך “and he was king in Jeshurun”.

עשה לך שתי חצוצרות כסף, seeing that the immediate plan was for the people to journey to the Holy Land without delay, G’d gave the commandment for the trumpets to be used as “Royal trumpet blasts,” announcing the moving of the Tabernacle to a new location, or announcing the arrival of the Tabernacle at its next location. The trumpets would also be blown before battles, as we know from verse 9.

עשה לך שתי חצצורות "make two trumpets for yourself." Why did Moses require trumpets to announce the journeys when all the Israelites could see the cloud move and this was their signal to commence packing and journeying? Perhaps the reason is that not all the tribes began their journey at the same time. The tribe of Yehudah was the first to break camp followed by the members of the clan of Gershon who carried the Tabernacle, followed by the camp of the tribe of Reuven, etc. The trumpets were required so that each group knew exactly when to start moving. When we questioned the need for the trumpets we could have also questioned why the trumpets were described as לך, "for yourself" i.e. for Moses. The fact is that just as G'd had paid Moses the compliment not to let the clouds move or come to rest without Moses telling it to, so G'd paid him the compliment of allowing him to give the signal to break camp by means of the trumpets. In that sense then the trumpets were Moses'. The word לך means that these trumpets would be at the exclusive disposition of Moses. Sifri on our verse understands the word to mean that Moses had to pay for these trumpets out of his own funds. Bamidbar Rabbah 15,15 suggests that only Moses was allowed to blow these trumpets. As there are 70 different ways to explain the Torah, all of these explanations are legitimate.