Proof by blatant assertion? We don't know how the Apostles kept the Sabbath. We do know that Ignatius of Antioch, who knew Peter, Paul, and certainly John, wrote in his epistles (on his way to martyrdom) congratulating his readers on "no longer sabbathing". Paul opposed imposing Jewish ceremonial practice on Gentile Christians, and that's exactly what Sabbath-keeping is.
You have conflated Gods Holy law with the temporal ceremonial laws which were to point to and remind them of the coming Messiah. The Ten Commandments were permanent. They were wrote in stone by Gods Finger. They were instituted at Creation. Re-instituted at Mt. Sinai. Lived out in the life of Jesus Christ on earth. Jesus kept the Sabbath in life and death. He is Lord of the Sabbath. He came not to destroy the Law but to fulfill it. Not one jot or tittle will be changed until earth and Heaven passes away and that has not happened. So it is still in force.