Dear Joseph Farah,
The verses that make keeping the Sabbath optional include:
Deuteronomy 18:15-19. For just as Moses was the one through whom God gave the 10-statement covenant (not Ten Commandments, Exodus 34:28, Deuteronomy 4:13), which in Exodus 20:2-17 consisted of an introduction giving the parties to the covenant followed by nine commands, and all its ancillary laws, one of which laws was that none of the laws were to be added to nor taken away, so this new prophet will present a new covenant.
Jeremiah 31:31-32, again the reference to the 10-statement covenant given at Horeb to be replaced.
Matthew 26:28, Mark 14:24, Luke 22:20: Jesus presented the new covenant which, by necessity, replaced the old covenant.
II Corinthians 3:14: The old covenant is no longer in force.
Hebrews 7:22: Jesus is the one who brought the new and greater covenant.
Hebrews 8:13: The old covenant has been made the old and no longer in force.
There are more verses that can be referenced.
One of the things pointedly missing from the New Covenant is the keeping of the Sabbath, made explicit in Romans 14.
If you want to keep the Sabbath on your own, go ahead. That’s part of Christian freedom. But don’t be a Pharasizer saying that it’s incumbent on all Christians to keep the law of the Old Covenant.
Karl W. Randolph