The first day of the lunar month was observed as a holy day. In addition to the daily sacrifice there were offered two young bullocks, a ram and seven lambs of the first year as a burnt offering, with the proper meat offerings and drink offerings, and a kid as a sin offering. (Numbers 28:11-15) As on the Sabbath, trade and handicraft work were stopped, (Amos 8:5) and the temple was opened for public worship. (Isaiah 66:23; Ezekiel 46:3) The trumpets were blown at the offering of the special sacrifices for the day, as on the solemn festivals. (Numbers 10:10; Psalms 81:3) It was an occasion for state banquets. (1 Samuel 20:5-24) In later, if not in earlier, times fasting was intermitted at the new moons. Judith 8:6. The new moons are generally mentioned so as to show that they were regarded as a peculiar class of holy days, distinguished from the solemn feasts and the Sabbaths. (1 Chronicles 113:31; 2 Chronicles 2:4; 8:13; 31;3; Ezra 3:5; Nehemiah 10:33; Ezekiel 45:17) The seventh new moon of the religious year, being that of Tisri, commenced the civil year, and had a significance and rites of its own. It was a day of holy convocation. The religious observance of the day of the new moon may plainly be regarded as the consecration of a natural division of time.
New Moon
In Israel the start of each month was marked as its own occasion. The law told the people to blow trumpets “in the beginnings of your months” and to bring burnt offerings, with bullocks, a ram, lambs and a goat for a sin offering. Chronicles lists the new moons beside the sabbaths and the set feasts as times for the Levites to offer sacrifice. Amos shows how the day could be abused, quoting merchants who are impatient for it to end so they can go back to selling grain and cheating with false scales. Numbers 28 sets out what was offered.
8 verses
Numbers
Also in the day of your gladness, and in your solemn days, and in the beginnings of your months, ye shall blow with the trumpets over your burnt offerings, and over the sacrifices of your peace offerings; that they may be to you for a memorial before your God: I am the LORD your God.
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;
And three tenth deals of flour for a meat offering, mingled with oil, for one bullock; and two tenth deals of flour for a meat offering, mingled with oil, for one ram;
And a several tenth deal of flour mingled with oil for a meat offering unto one lamb; for a burnt offering of a sweet savour, a sacrifice made by fire unto the LORD.
And their drink offerings shall be half an hin of wine unto a bullock, and the third part of an hin unto a ram, and a fourth part of an hin unto a lamb: this is the burnt offering of every month throughout the months of the year.
And one kid of the goats for a sin offering unto the LORD shall be offered, beside the continual burnt offering, and his drink offering.
1 Chronicles
And to offer all burnt sacrifices unto the LORD in the sabbaths, in the new moons, and on the set feasts, by number, according to the order commanded unto them, continually before the LORD:
Amos
Saying, When will the new moon be gone, that we may sell corn? and the sabbath, that we may set forth wheat, making the ephah small, and the shekel great, and falsifying the balances by deceit?
From Smith's Bible Dictionary
William Smith, 1884