When the Light came in the personality of Jesus, the old Mosaic law having fulfilled its function of preparing the Jews for the coming of the Messiah was abrogated as regards its ceremonial prescriptions in favor of the new dispensation or law of Christ.
To signalize this transition from the old to the new law, the Apostles transferred the observance to the Sunday, the first day of the week.
Note the following quote, which makes this claim: Under the Old law, the Sabbath or seventh day of the week was observed because on that day God rested from his labors of creation ...
The Old Law was but an image or foreshadowing of the Light and Truth that was to come.
This meeting will be dealt with below when discussing John . Until Jesus actually appeared to them they thought He was still dead, despite having been told by Mary Magdalene that she had seen the risen Lord!