In John 20, Jesus appears to Mary Magdalene and His disciples. First, He appeared to Mary Magdalene. She did not recognize Him until He called her by name. Next He appeared to the disciples on two different days. They also hesitated before they were able to see that it was Jesus. Thomas even needed to see Jesus' wounds before he believed. What all these events have in common is that they all happened on a Sunday, NOT the Sabbath. This is when Sunday became the Lord's Day. The most convincing proof that Jesus was really resurrected is that Jews, who had worshipped on the Sabbath or Saturday for thousands of years suddenly switched to Sunday on that first Sunday and on the next Sunday Thomas joined them and we disciples have been worshipping on Sunday ever since.