Indeed, the Sabbath day was the prescribed day of worship in the Law of Moses. Exodus 20:8, 11: “Remember the Sabbath day, to keep it holy. ... For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the LORD blessed the Sabbath day, and hallowed it."
In Leviticus 26:2, again we read: “You shall keep My Sabbaths and reverence My sanctuary: I am the LORD.”
So, why don't we keep the Sabbath today? Quite simply, we are not so commanded. The observance of the Sabbath was commanded in the Law of Moses, which was given to the nation of Israel. In Deuteronomy 4:44-45 we read, “And this is the law which Moses set before the children of Israel: These are the testimonies, and the statutes, and the judgments, which Moses spake unto the children of Israel, after they came forth out of Egypt.”
The New Testament reveals time and again that we are no longer subject to the Law of Moses. Notice what the inspired writer, the Apostle Paul, said: “Having abolished in His flesh the enmity, even the law of commandments contained in ordinances; for to make in Himself of twain one new man…” (Ephesians 2:15)
Again, Paul wrote the same message to the Colossians. Hear his words: “Blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross…” (Colossians 2:14)