We are told that Jesus came to fulfill the Law (Law of Moses which included the 10 commandments). This is found in Matthew 5:17.

During Jesus teaching he reaffirmed 9 out of the 10 commandments, often with greater detail (eg Matthew 5:21). The only one he never mentioned is the Sabbath commandment. None of the apostles gave instructions to keep it either. In fact, nowhere in the New Testament is the follower of Christ commanded to keep the Jewish Sabbath.

There are a number of other verses which are interesting to consider on this subject. These suggest to me that while it is not a sin to keep the sabbath, it would be wrong to insist that not keeping it is sinning.

* Galatians 4:9-10 But now that you know God - or rather are known by God - how is it that you are turning back to those weak and miserable principles? Do you wish to be enslaved by them all over again? You are observing special days (sabbath?) and months and seasons and years!

* Romans 14:5-6 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. He who regards one day as special, does so to the Lord...

* Colossians 2:16 Therefore do not let anyone judge you by what you eat or drink, or with regards to a religious festival, a New Moon celebration or a Sabbath Day.

In Acts 20:7 and 1 Corinthians 16:2 we read of the early apostles and disciples gathering on the first day of the week (Sunday) to remember Jesus. Nowhere is this spoken against. Quite possible this started for practical reasons and has continued. It must be noted though that Sunday has not been chosen as a replacement for the Sabbath. It has not been classified as a "holy day"

Jesus' commandment in Luke 22:10 was to "do this in remembrance of me" and in 1 Corinthians 11:26 | Paul adds the comment "For whenever you eat this bread and drink this cup...". No mention of a day or length of time between, but 'whenever'.