Originally Posted by AV1611

My apologies, I don't quite understand your point here. The text I provided is an explicit command from YHWH that Israel are to worship him three times a year in Jerusalem; at the feast of unleavened bread, the feast of weeks, and the feast of tabernacles. And really the 1 Kings text is refering to the feast of tabernacles. The point is that the sin of Jeroboam is not so much the creation of holy days but the perversion of the worship YHWH commanded. Instead of male Israelites going to Jerusalem to worship before YHWH at the Feast of Tabernacles, Jeroboam caused male Israelites to go to Bethel or Dan to worship YHWH at a feast immitating Tabernacles a month later. The sin of Jeroboam then, is a transgression of an explicit command of God.

The implication of this is that a rival worship is forbidden, not that we can only worship as he has commanded. If God commands us to worship him on Sunday then we must worship him on Sunday, but it does not therein follow that we must not worship him on Monday. That is, we must not transgress an explicit command of God as regarding his worship.