History records to us that early on in Acts, the Christians went to meeting now on Sunday, as that was the day recorded down by all of the early Church fathers as the time they gathered and met!
Questions for y'all.
- What mandatory feast were the disciples celebrating?
- What was the unexpected event?
- How many days after the last Sabbath during Passover did this event happen?
- When was this feast mandated?
- On what day of the week is the Sabbath of the Jews?
You see the Feast of Pentecost happens 50 days after the last Sabbath in the 8 days of Passover. Pentecost is on a Sunday. Since Holy Spirit came to the Disciples on that day, this day is the "Birthday of the Church".
Using any calendar, and counting forward from the last Sabbath in Passover you will find that the 50th day always falls upon Sunday. Therefore it was Moses, the Lawgiver, who wrote the instructions from God for Pentecost c 1200 BC.
That is why Christians (which I exclude SDAs) uniformly worship on Sunday. Is that just a coincidence? Hardly so!