The 4th Commandments

Exodus 20:8-11

Remember the Sabbath day, to keep it holy.  Six days shalt thou labour,and do all thy work:  But the seventh day is the Sabbath of the Lord thy God: in it thou shalt not do any work, thou, nor thy son, nor thy daughter, thy manservant, nor thy maidservant, nor thy cattle, nor thy stranger that is within thy gates:  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.:

God instituted the Sabbath to Israel as a weekly reminder of two things. First is that all true blessing comes from His grace, not their labor. Secondly, that they should hallow him and honor Him and keep the day holy so to seek the fullness of His blessing by there giving our special attention to Him on the 7th day of each week.  Remember the Law, i.e., the Ten Commandments and everything in Deuteronomy was given unto Israel not unto the world at large like Jesus' crucifixion was.

 Deuteronomy 5 explains why the Israelite were to keep the Sabbath holy:  Verse 15: 

"You shall remember that you were a servant in the land of Egypt, and the Lord your God brought you out thence with a mighty hand and an out stretched arm; therefore the Lord your God commanded you to keep the Sabbath day."  Christians were not carried out of Egypt so this reason does not apply to those under the Blood and not under the Law.  So I am not convinced that this injunction against laboring on the Sabbath holds for Christians.  And it would be a good thing if we were not for Christians have not observed the Sabbath since the beginning of the church almost.  The Sabbath commandment does not require worship, it prohibits work. Worship can occur on any day.  And the Sabbath's constrain against work is directed to the Jews, not Christians.

The early church did observe the Sabbath but the apostles had a meeting to decide which of the Jewish laws apply to non-Jewish Christians. Their decision is recorded in Acts 15:24-29. If you read it carefully, there is nothing in there about the Sabbath. Any modern Jewish rabbi would agree—the Sabbath law only applies to Jews. If you want to keep the Sabbath holy, you can but since Jesus rose from the grave on Sunday, that is the best day to celebrate it in worship.  

The point?  If you are stressing over not keeping the Sabbath holy by working on Saturday and/or Sunday as well, well don't it is of no consequence.