Sabbath-keeping with all it's rules and regulations, was part of a covenant with Israel that is not applicable to Christians under the New Covenant. Even when Christians set out to worship on the Sabbath, they aren’t truly "keeping the Sabbath." To "keep the Sabbath" as it was required in the Old Testament would involve compliance with stringent regulations (Exodus 16:23; 35:3; Leviticus 23:32; Jeremiah 17:21) that were strictly enforced.
If Sabbath-day observances are still required, so would the burnt offerings which went along with them (Leviticus 19:30; 23:2-3; Numbers 28:1-10; 29:39-40; I Chronicles. 23:30-31; II Chronicles 31:2-4; Isaiah 1:13). These were commanded by God to the sons of Israel. If the seventh-day Sabbath is still in affect, then why do not the Sabbatarians seek to obey ALL that the LORD commanded? How can a person say he keeps a certain law when he keeps only part of it?
If the Sabbath-day laws were still in effect today, then according to Exodus 31:12-18; 35:1-3; and Numbers 15:32-36, anyone who profaned the Sabbath was put to death and any person who does any work on it, that person shall be cut off from his people. Who is going to enforce that? The Jewish synagogue? The Christian Church? The Seventh-day Adventist church? Or the State? Since we do not live under a theocratic state as ancient Israel did, no Sabbatarian can live consistently under the Mosaic regulations.
St. Paul said in Galatians 4:9-11: "...You observe days and months and seasons and years. I fear for you, that perhaps I have labored over you in vain."
In Romans 14:1-23, the Apostle Paul says: "... One man regards one day above another, another regards every day alike. Let each man be fully convinced in his own mind...(NASB)." In other words, for the Christian, the Apostle is saying that no day is to be regarded holier than another. Although the Torah was read every Saturday in the synagogues, the early Gentile Christians were never commanded to be circumcised, or to rest on Saturday as the Jews were (Acts 15:1-21).
In Colossians 2:16-17, the Apostle Paul also said 16 Therefore no one is to act as your judge in regard to food or drink or in respect to a festival or a new moon or a Sabbath day 17 things which are a mere shadow of what is to come; but the substance belongs to Christ.