The Jewish day is from evening to evening. So Fri. evening till Sat. evening is the Sabbath. The Sabbath was simply a day of rest for man and animal. and was given to the Jew. Paul always went to the Jewish Temples to preach the Gospel to the Jew first, but the first day of the week, The church always met for fellowship, teaching and praising the Lord. The Sabbath was not changed, but the Church is not under law, but under the law of Christ. In my time, that is why there was no work on Saturday or Sunday for Jew and Gentile and a law called the Blue Law that stores on Sunday could not sell anything that had to do with work....but only food and were only open for about four hours. The Blue Law is still on the books but as the world turns more vial and immoral, God is ignored.