For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Larry Truelove
The Sabbath always has been Saturday. However, the Sabbath requirement to cease work was only given under the law, which was fulfilled for believers in Jesus Christ. Hebrews 4 uses the literal Sabbath observance typologically to its ultimate fulfillment in Christ. That chapter speaks of two types of "rest" (emphasis on REST), creation week rest and promise land rest. It cites Psalm 95 prophetically of a Rest of faith in Christ.
Dan Dao
The bible says remember the sabbath day and keep it holy. Keep yourself from work and worship the Lord. The seventh day after working for six days varies from place to place. I think from a different view after reading your answers that, What is important is that the appointed day you have rest that you should take time and worship the Lord. Remember it and keep it holy for its Gods desire you do it. I think when God created the heavens and the earth it's not indicated in the bible the day He begun His work, but after six days He rested and gave us a command to observe that. Many people want others to observe their days, however God is a God of order make sure as you set a worship day for the Lord make sure you observe it and keep it holy.
Larry Truelove
At creation, there was no command for mankind to keep the sabbath day holy nor to worship and refrain from work. That was only given to the Israelites during their exodus from Egypt under the leadership of Moses.
Crystal Guyer
I'm still confused and I'm 69 years old! I was brought up Catholic and we went to mass on SUNDAY; my eldest daughter has become a 7th Day Adventist so she celebrates the Sabbath from sundown Friday to sundown Saturday.
The problem as I see is is that there's NOWHERE in the Bible that states which day of the week was the "first day" that God started to make the world. Did He start on Sunday, making Saturday the Sabbath? Did He start on Monday, making Sunday the Sabbath? Or did He start on Wednesday, making Tuesday the Sabbath, and so on? Do you see why I'm still confused?
Gary Wainwright
Crystal, the below links I believe will answer to your question about the Sabbath.
https://www.gotquestions.org/Saturday-Sunday.html
https://www.gotquestions.org/Christian-Sabbath.html
https://www.gotquestions.org/Sabbath-keeping.html