Before you start observing the Sabbath day first examine a few facts you need to know. Ask yourself these few questions and answer them based upon new testament scripture.
What nation did God authorize the seventh day Sabbath Rest? “It (the Sabbath) is a sign between me and the children of Israel” (Ex. 31:17). Why were the children of Israel commanded to keep the Sabbath (Saturday)? “And remember that you was a servant in the land of Egypt, and that the Lord thy God brought you out there through a mighty hand and by a stretched out arm: therefore (because of this} the Lord thy God commands you to keep the Sabbath day” (Duet. 5:15). The Gentile nation was not in this Egyptian bondage, and should not keep this day as a nation.
When was the Sabbath made binding upon the Jewish nation? “You came down also upon Mount Sinai… and made known thy holy Sabbath by the hand of Moses” (Neh. 9:13-14). The Sabbath was not kept from creation down to the receiving of the law by Moses on Mount Sinai as some teach.
Was the Seventh Day Sabbath law ever to be taken away? Yes! Note the following: When will the Sabbath be gone?” (Amos 8:5). “In that day, said the Lord God, that I will cause the sun to go down at noon, and I will darken the earth in the clear day.”(Amos 8:6). When Jesus died on the cross “THERE WAS DARKNESS OVER ALL THE LAND FROM THE SIXTH HOUR (12 noon) UNTIL THE NINTH HOUR (3:00 P.M.)” (Matt. 27:45). The death of Jesus on the cross was the time when, and the place where, the Sabbath was taken away.
Did God ever break the covenant which contained the Seventh Day Sabbath law? Yes! “And I took my staff, even Beauty (Christ), and cut it asunder, THAT I MIGHT BREAK MY COVENANT WHICH I HAD MADE WITH ALL THE PEOPLE, AND IT WAS BROKEN IN THAT DAY” (Zech. 11:10-11). The day the Sabbath covenant was broken was the day it was nailed to the cross with Jesus (Col. 2:14-16). This Sabbath covenant died when Christ died.
Were people ever told in the New Testament to “Remember The Sabbath Day To Keep It Holy”? No! The Jews who rejected Christ and his teaching continued to meet on the Sabbath day. Some Gentile proselytes to Judaism also met on the Sabbath with the Jews. Paul and some others met at this time with them because it gave them an audience to preach to, and to tell them that, “THEY SHOULD WORSHIP GOD CONTRARY TO THE SABBATH LAW?” (Acts 18:13) He emphasized to the Jews that the things “written and engraved in stones” were done away in Christ. (Col. 2:14-16 f; 2 Cor. 3:7-14).
What events make the first day of the week the outstanding day of the New Testament? Jesus arose on the first day (Mk. 16:9). Christ regularly met with his disciples after his resurrection on the first day (Jn. 20:1, 19, 26). Pentecost came on the first day (Lev. 23:15-16), therefore every event recorded in the second chapter of Acts happened on the first day of the week. Like, for instance: the apostles were baptized with the Holy Spirit on the first day. The first gospel sermon proclaiming Jesus to be the Son of God was preached on the first day of the week. The first three thousand were added to the church on the first day. The church assembled on the first day to break bread or to observe the Lord’s Supper, and to give of their means (Acts 2:42 ff, Acts 20:7, 1 Cor. 16:1-2, 1 Cot. 11:23-33, Heb. 10:25).
Conclusion: Based upon these facts in the New Testament, no Christians should be observing the Sabbath day as a day of worship. Jesus nailed to His cross the entire law of Moses which God gave to him on Mt. Sinai, which included the 10 commandments, wherein is contained the law of the Sabbath (Col 2:14-16 ff; Eph 2:13-16).