The following scriptures state to worship on the new moons:
Ezekiel 46:3 "Likewise the people of the land shall worship at the door of this gate before the Lord in the Sabbaths and in the new moons."
Isaiah 66:23 "And it shall come to pass, that from one new moon to another, and from one Sabbath to another, shall all flesh come to worship before me, saith the Lord."
Most scriptures concerning the new moons refer to burnt offering unto the Lord:
Amos 8:5 "Saying, When will the new moon be gone, that we may sell corn? and the sabbath, that we may set forth wheat,"
Numbers 10:10 "Also in the day of your gladness, and in your solemn days, and in the beginings 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."
Numbers 28:11 "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;"
1 Samuel 20:5 "And David said unto Jonathan, Behold, to morrow is the new moon, and I should not fail to sit with the king at meat: but let me go, that I may hide myself in the field unto the third day at even."
1 Samuel 20:18 "Then Jonathan said to David, To morrow is the new moon: and thou shalt be missed, because thy seat will be empty."
2 Kings 4:22-23 "And she called unto her husband, and said, Send me, I pray thee, one of the young men, and one of the asses, that I may run to the man of God, and come again. And he said, Wherefore wilt thou go to him to day? it is neither new moon, nor sabbath. And she said, It shall be well."
2 Chronicles 2:4 "Behold, I build an house to the name of the Lord my God, to dedicate it to him, and to burn before him sweet incense, and for the continual shewbread, and for the burnt offerings morning and evening, on the Sabbaths, and on the new moons, and on the solemn feasts of the Lord our God. This is an ordinance for ever to Israel."
2 Chronicles 8:13 "Even after a certain rate every day, offering according to the commandment of Moses, on the Sabbaths, and on the new moons, and on the solemn feasts, three times in the year, even in the feast of unleavened bread, and in the feast of weeks, and in the feast of tabernacles."
2 Chronicles 31:3 "He appointed also the king's portion of his substance for the burnt offerings, to wit, for the morning and evening burnt offerings, and the burnt offerings for the Sabbaths, and for the new moons, and for the set feasts, as it is written in the law of the Lord."
Nehemiah 10:32-33 "Also we made ordinances for us, to charge ourselves yearly with the third part of a shekel for the service of the house of our God; For the shewbread, and for the continual meat offering, and for the continual burnt offering, of the sabbaths, of the new moons, for the set feasts, and for the holy things, and for the sin offerings to make an atonement for Israel, and for all the work of the house of our God."
Ezra 3:5 "And afterward offered the continual burnt offering, both of the new moons, and of all the set feasts of the Lord that were consecrated, and of every one that willingly offered a freewill offering unto the Lord."
Psalms 81:3 "Blow up the trumpet in the new moon, in the time appointed, on our solemn feast day."
Isaiah 66:22 "For as the new heavens and the new earth, which I will make, shall remain before me, saith the LORD, so shall your seed and your name remain."
Ezekiel 46:1-3 "Thus saith the Lord GOD; The gate of the inner court that looketh toward the east shall be shut the six working days; but on the sabbath it shall be opened, and in the day of the new moon it shall be opened. And the prince shall enter by the way of the porch of that gate without, and shall stand by the post of the gate, and the priests shall prepare his burnt offering and his peace offerings, and he shall worship at the threshold of the gate: then he shall go forth; but the gate shall not be shut until the evening. Likewise the people of the land shall worship at the door of this gate before the LORD in the sabbaths and in the new moons."
Hosea 2:11 "I will also cause all her mirth to cease, her feast days, her new moons, and her sabbaths, and all her solemn feasts."
Colossians 2:16 " Let no man therefore judge you in meat, or in drink, or in respect of an holyday, or of the new moon, or of the sabbath days:"
What are the scriptural arguments against keeping them as Sabbaths:
So the question is, does worshipping or giving offerings on the new moon make it a Sabbath no work and such? What can be said for certainty is that the new moon is to be observed in worship to the Lord and a memorial of God's established calendar for all mankind. The observance of the New Moon keeps God's people in remembrance of His true calendar and its High Days.
Observance of the New Moon is an observation of a commemorative meal.
The Church of God Proclaimed