The sabbath was created for all mankind. There were no Jews/Israelites in Genesis, at that time all mankind were gentiles.
Genesis 2
1 And the heaven and the earth were finished, and all the host of them.
2 And on the seventh day God finished His work which He had made; and He rested on the seventh day from all His work which He had made.
3 And God blessed the seventh day, and hallowed it; because that in it He rested from all His work which God in creating had made.
In the above verses we have God blessing and sanctifying the seventh day. Making the seventh day holy.
Exodus 20
8 Remember the sabbath day, to keep it holy.
Exodus 20
10 but the seventh day is a sabbath unto YHWH thy God, in it thou shalt not do any manner of work, thou, nor thy son, nor thy daughter, nor thy man-servant, nor thy maid-servant, nor thy cattle, nor thy stranger that is within thy gates;
In the two verses above we see once again, that the seventh day is holy, and we now see that this day is called 'the sabbath'. The seventh day of the week is the sabbath. Over time the numbers given to the days of the week, were replaced by names. Saturday was the name given to the seventh day.
The weekly sabbath day is a foretaste of the "rest" of the millennial kingdom. The Bible is replete with instructions pointing out how to keep the sabbath, the meaning of the sabbath, the blessings of keeping the sabbath, and why the seventh day of the week is important to mankind. Keeping the sabbath allows you to practice, and prepare yourself for the millenial kingdom.
Sabbath Will Be Kept in the Millennium
Isaiah 66
22 For as the new heavens and the new earth, which I will make, shall remain before Me, saith YHWH, so shall your seed and your name remain.
23 And it shall come to pass, that from one new moon to another, and from one sabbath to another, shall all flesh come to worship before Me, saith YHWH.
In the verse above we can see that ALL flesh are to worship before YHWH, on the sabbath.
Revelation 14
12 Here is the patience of the saints: here are they that keep the commandments of God, and the faith of Jesus.
Remember that the faith of Yehoshua is Judaic, though it didn't have a name at the time that Yehoshua practiced it.
Revelation 22
14 Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city.
Keeping the sabbath is the 4th commandment, aand part of the Mosaic Covenenat which we are told is Eternal/Everlasting. At no point has YHWH changed the 4th commandment. YHWH sanctified the Sabbath, Saturday. The Sabbath is YHWH's day. That is from YHWH, and not man-made like SUNday worship, via the 'edict' of Constanintine, in veneration of the Sun.
Constantine placed no Christian appellation upon the worship on the first day of the week, referring to it as the "venerable day of the sun."
Let all judges and all city people and all tradesmen rest upon the venerable day of the sun. But let those dwelling in the country freely and with full liberty attend to the culture of their field; since it frequently happens that no other day is so fit for the sowing of grain or the planting of vines; hence, the favorable time should not be allowed to pass, lest the provisions of heaven be lost. Quoted in Blakely, p. 269
Or if you prefer the Codex Justinianus:
On the venerable Day of the Sun let the magistrates and people residing in cities rest, and let all workshops be closed. In the country, however, persons engaged in agriculture may freely and lawfully continue their pursuits; because it often happens that another day is not so suitable for grain-sowing or for vine-planting; lest by neglecting the proper moment for such operations the bounty of heaven should be lost. (Given the 7th day of March, Crispus and Constantine being consuls each of them for the second time [A.D. 321].) Source: Codex Justinianus, lib. 3, tit. 12, 3; trans. in Philip Schaff, History of the Christian Church, Vol. 3 (5th ed.; New York: Scribner, 1902), p. 380, note 1.
Mark 2
27 And he said unto them, The sabbath was made for man, and not man for the sabbath:
28 Therefore the Son of man is Lord also of the sabbath.
The Sabbath is YHWH's Day."