What is the origin of the Sabbath?

When the day of rest was introduced, sin has not been known yet by Adam and Eve. They were not Jews to whom God had entrusted the keeping of the day. When that faulty argument that the Sabbath was given to the Jews and not the Christians or believers is not tenable, the theologians et al pull from their arsenal another weapon which points out that nowhere in Genesis it is written that God enjoined Adam and Eve to keep the Sabbath or that they even kept the Sabbath. If those assertions would be correct, the original sin would have turned out to be the refusal of the dismissive Adam and Eve to join God in His Sabbath rest, while they were busy doing 'je ne sais quoi'. The Christian detractors of the Sabbath also claim that the Sabbath was done away with at the Cross. But, is there anything in Genesis 2:1-3 that suggests that the Sabbath needed redemption? The cross has to do with the disobedience of our first parents that demanded the shedding of their blood (death), hence, our blood, and their (our) redemption. In other words, the Sabbath day did not sin but preceded sin and has nothing to do with the sacrifice of Jesus. The popularity of those false doctrines are not the random rebellious reactions customary of mankind.  It was prophesied in 2 Timothy 4:3-4 that many disguised agents of the Deceiver will tell fables about God and that many will subscribe to their teachings:

2 Timothy 4:3-4 KJV
(3) For the time will come when they will not endure sound doctrine; but after their own lusts shall they heap to themselves teachers, having itching ears; (4) And they shall turn away their ears from the truth, and shall be turned unto fables.

As you might understand, the Sabbath precedes the arrival of the Jews and begins with Adam and Eve down to each of us today, unless we claim a different evolutionary path than Adam and Eve. Even if we do, the animals had no choice but rest as God did, unless we put them to work (Exodus 20:10).

In promulgating His Sabbath day of rest at Sinai, God gave to the Israelites the reason why He is commanding them to keep the day. He cited Genesis 2:1-3 to them.

Ultimately, no matter where the Sabbath comes from and because God promulgates it in the Old Testament, sends Prophets to warn about not keeping it, welcomes any pagan to Judaism to keep it (Isaiah 56), Matthew 5:17-18 seals the Sabbath as forever binding.

Matthew 5:17-18 KJV
(17) Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil. (18) For verily I say unto you, Till heaven and earth pass, one jot or one tittle shall in no wise pass from the law, till all be fulfilled.

Furthermore, we read that the Sabbath belongs to Jesus (Mark 2:28), which makes Him YHWH God, the Logos of the Book of Genesis.