In the beginnings of your months... — The beginning of the month was announced by the blowing of the silver trumpets (Numbers 10:10). Increased respect was paid to the beginning of the month in later times. Trade was suspended (Amos 8:5), and religious instruction appears to have been given at this time (2 Kings 4:23).
Related Commentaries of Numbers 28:11
Numbers 28:11
11 And in the beginnings of your months ye shall offer a burnt offering unto the LORD; two young bullocks, and one ram, seven lambs of the first year without spot;