“And The Lord Spoke to Moses,” Numbers 10.

And the Lord spoke to Moses, saying: “Make two silver trumpets for yourself; you shall make them of hammered work; you shall use them for calling the congregation and for directing the movement of the camps. Also in the day of your gladness, in your appointed feasts, and at the beginning of your months, you shall blow the trumpets over your burnt offerings and over the sacrifices of your peace offerings; and they shall be a memorial for you before your God: I am the Lord your God.” And it shall be, if you go with us—indeed it shall be—that whatever good the Lord will do to us, the same we will do to you.” And the cloud of the Lord  was above them by day when they went out from the camp. So it was, whenever the ark set out, that Moses said: “Rise up, O Lord! Let Your enemies be scattered, And let those who hate You flee before You.” And when it rested, he said: “Return, O Lord, To the many thousands of Israel.”
Numbers 10:1-2,10,32,34-36 - hNKJV