In Exodus 31, God tells the Children of Israel, “This will be a sign between Me and you” and “It will be a sign between Me and the Israelites forever” which was always understood by Jews to indicate non-Jews had no such specific obligation.
It was a shock to many Jews that Gentiles could be saved. Romans 9:25,26 25As He says in Hosea: “I will call them My people who are not My people, and I will call her My beloved who is not My beloved,” 26and, “It will happen that in the very place where it was said to them, ‘You are not My people,’ they will be called ‘sons of the living God.’”
This where the grafting of Gentiles into the Chosen People occurs. Mark 2:27Then He said to them, "The Sabbath was made for Jews man, not Jews man for the Sabbath.