I'm not sure how other Christian Religions teach the difference but in Catholic Church a moral command isn't subject to change, ever. Natural Law or Moral law would be those laws that a person is commanded by nature to observe, such as honoring your parents, not stealing, murder, etc.
Ceremonial commands are always activated by times and seasons such as observing a certain feast or observance of a Sabbath. Because a person isn't commanded by nature to observe a Sabbath like they are commanded by nature to "not steal" one can be positive that a Sabbath isn't a moral command. It fails on all counts as Adam nor anyone after Adam up to the time of Moses observed a Sabbath while everyone from Adam on knew it was wrong to murder, steal, etc.
Work does not go against the nature of God. In the Genesis account and up to Moses the Sabbath is described as belonging to God. "Tomorrow is a Sabbath to God", etc, etc.
In Jewish understanding Adam and Eve were created and sinned on the 6th day and thrown out of the Garden "prior" to entering the Rest of God. This is not a new understanding it's as old as the book of Lev. This is why Scripture describes the Sabbath as "God's Rest".
Ex 16,23
Ex 16, 25, etc.
In the New Testament Scriptures we are told that the New Heaven and Earth does not have night. Sabbath was ment to be perpetual and our first parents were created in "live in it". This is what Jesus means when He says that we find "Rest" in Him. At least that's my take on it.