“Gen 2:3 And God blessed the seventh day, and sanctified it: because that in it he had rested from all his work which God created and made.” says God blessed the 7th day and sanctified it (set is apart for holy purpose) after he had rested from all his work. We can say that He sanctified the day and blessed it on the 1st day of 2nd week.
If the 7th day is not going to be a day of worship and a holy day then there is no real meaning of sanctifying and blessing it after He had rested on that day.
Sabbath was made for mankind Mark 2:27 as a sign of creation. That is why we have 130plus cultures where the 7th day is called as Sabbath.
Also there are cultures where they have kept Sabbath historically without any relationship to Bible. For example Nepal’s national holiday is saturday. In India there is a scheduled tribe which has no connection to the outside world and they keep every 7thday as holy day.
According to reliable estimates, Africa has the world’s largest concentration of Sabbath-keepers, some 20 million people, of which only about three million are Seventh Day Adventists. The Sabbath is natural to Africans. The Sabbath is thriving in Africa because the Sabbath roots of Africa run deep, both in Scripture, and historical practice.
W. W. Oliphant, an African church leader in the early years of the twentieth century says that the “Sabbath in Ethiopia [has] been kept from the days of Nimrod, about 2140 B.C. (read Gen. 10:8, 10), that is 700 years before the birth of Moses. . . . Africans or Ethiopians had been Sabbath observers from the days of Nimrod” (Quoted in Bradford C.E. Sabbath Roots, The African Connection. L. Brown and Sons, Barre (VT), 1999, p. 26).
In Ethiopia in the fourth century, Frumentius reported:
“And we assemble on Saturday,” he continues ; “not that we are infected with Judaism, but to worship Jesus, the Lord of the Sabbath” (Davis, Tamar. A General History of the Sabbatarian Churches. 1851; Reprinted 1995 by Commonwealth Publishing, Salt Lake City, pp. 41-42).
Notice some of the statements by Ethiopian Emperor Galawdewos (A.D. 1540-1559):
We do celebrate the Sabbath, because God, after He had finished the Creation of the World, rested thereon…and that especially, since Christ came not to dissolve the law but to fulfill it. It is therefore not in the imitation of the Jews, but in obedience to Christ, and His holy apostles, that we observe that day (Quoted in Bradford C.E. Sabbath Roots, The African Connection. L. Brown and Sons, Barre (VT), 1999, p. 26).
When God gave the 4th commandment He points to the creation account as a reason for keeping the 7th day Holy.
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. Exo 20:11.
Can you see something interesting.. man takes rest after working in the day. Work comes first and a rest follows. Similarly we work throughout the week and rest in the end. I want you to seriously think this. If there was no sabbath until Sinai (as people teach) then man would have worked throughout the week without rest.
It is great thing for God to have created Sabbath isn’t it. So man can work and take rest also.
The great Planner planned it in that way. If God has not created sabbath there would have been no harmony on which day man would have gathered to worship. Each would have preferred a day for worshiping God. I am not talking about the personal devotion with God but the gathering of people to worship.
Luke recognized the 7th day as sabbath day because though he is gentile he always refer to it as sabbath day rather than calling it as Saturday (in his language). [it is ironical to see a non observer of sabbath for example a Baptist to refer Saturday as sabbath. He would refer it as Saturday. Only a sabbath keeper would prefer to refer it as sabbath instead of Saturday]
John says that he was in spirit on the Lord’s day. The only day Bible ever recognizes as Lord’s day is Sabbath.
Sabbath will be the sign of creation and a day of rest even in the new heaven and new earth. Isa 66:22,23