Numbers 10:1

And the LORD spake unto Moses, saying,

The opening words introduce the Lord's instructions to Moses establishing a trumpet system to organize Israel's movements and communicate commands, keeping the whole camp in perfect order and thorough discipline. Moses was to pass those directions to the sons of Aaron, who were to march just behind Moses and Aaron and in front of the ark bearing the trumpets to make Moses's directions known to the people. The trumpets were to give distinct, special, certain sounds that the people knew and understood for pitching camp and journeying, with a special first signal calling all to attention and the sound that followed directing what to do, so there was no confusion of sound. Under that signaling the people were to move by tribes in order in companies under their own standards, with appointed leaders and the head officer of each company giving definite directions, while the Levites held assigned duties around the ark and tabernacle including carrying the sacred ark.

Failure to comply with what the Lord gave to Moses for the people was punished with death. Ignorance was no excuse for disobedience or confusion of movement, because all had the same opportunity to learn the signals and requirements, leaving no excuse for confusion, so that not knowing was as great a wrong as hearing and yet transgressing. The arrangement proves God to be a God of order, as particular now as then, requiring discipline, harmony, and union of action in His work.