There are many things about Puritan/Reformed theology I whole-heartedly agree with, but keeping the Sabbath is not one of them. This is a good article to explain my position on this issue.
In Colossians 2:16-17, the apostle Paul declares, “Therefore do not let anyone judge you by what you eat or drink, or with regard to a religious festival, a New Moon celebration or a Sabbath day. These are a shadow of the things that were to come; the reality, however, is found in Christ.” Similarly, Romans 14:5 states, “One man considers one day more sacred than another; another man considers every day alike. Each one should be fully convinced in his own mind.” These Scriptures make it clear that, for the Christian, Sabbath-keeping is a matter of spiritual freedom, not a command from God. Sabbath-keeping is an issue on which God’s Word instructs us not to judge each other. Sabbath-keeping is a matter about which each Christian needs to be fully convinced in his/her own mind.
In the early chapters of the book of Acts, the first Christians were predominantly Jews. When Gentiles began to receive the gift of salvation through Jesus Christ, the Jewish Christians had a dilemma. What aspects of the Mosaic Law and Jewish tradition should Gentile Christians be instructed to obey? The apostles met and discussed the issue in the Jerusalem council (Acts 15). The decision was, “It is my judgment, therefore, that we should not make it difficult for the Gentiles who are turning to God. Instead we should write to them, telling them to abstain from food polluted by idols, from sexual immorality, from the meat of strangled animals and from blood” (Acts 15:19-20). Sabbath-keeping was not one of the commands the apostles felt was necessary to force on Gentile believers. It is inconceivable that the apostles would neglect to include Sabbath-keeping if it was God’s command for Christians to observe the Sabbath day.
A common error in the Sabbath-keeping debate is the concept that the Sabbath was the day of worship. Groups such as the Seventh Day Adventists hold that God requires the church service to be held on Saturday, the Sabbath day. That is not what the Sabbath command was. The Sabbath command was to do no work on the Sabbath day (Exodus 20:8-11). Nowhere in Scripture is the Sabbath day commanded to be the day of worship. Yes, Jews in Old Testament, New Testament, and modern times use Saturday as the day of worship, but that is not the essence of the Sabbath command. In the book of Acts, whenever a meeting is said to be on the Sabbath, it is a meeting of Jews and/or Gentile converts to Judaism, not Christians.
When did the early Christians meet? Acts 2:46-47 gives us the answer, “Every day they continued to meet together in the temple courts. They broke bread in their homes and ate together with glad and sincere hearts, praising God and enjoying the favor of all the people. And the Lord added to their number daily those who were being saved.” If there was a day that Christians met regularly, it was the first day of the week (our Sunday), not the Sabbath day (our Saturday) (Acts 20:7; 1 Corinthians 16:2). In honor of Christ’s resurrection on Sunday, the early Christians observed Sunday not as the “Christian Sabbath” but as a day to especially worship Jesus Christ.
Is there anything wrong with worshipping on Saturday, the Jewish Sabbath? Absolutely not! We should worship God every day, not just on Saturday or Sunday! Many churches today have both Saturday and Sunday services. There is freedom in Christ (Romans 8:21; 2 Corinthians 3:17; Galatians 5:1). Should a Christian practice Sabbath-keeping, that is, not working on Saturdays? If a Christian feels led to do so, absolutely, yes (Romans 14:5). However, those who choose to practice Sabbath-keeping should not judge those who do not keep the Sabbath (Colossians 2:16). Further, those who do not keep the Sabbath should avoid being a stumbling block (1 Corinthians 8:9) to those who do keep the Sabbath. Galatians 5:13-15 sums up the whole issue: “You, my brothers, were called to be free. But do not use your freedom to indulge the sinful nature; rather, serve one another in love. The entire law is summed up in a single command: ‘Love your neighbor as yourself.’ If you keep on biting and devouring each other, watch out or you will be destroyed by each other.”