The rules governing how far a person could walk on the Sabbath made it difficult to travel to the synagogue, and then walk during the day to another place where Christians gathered for the Eucharist.
The Sabbath began at sunset on Friday, and ended at sunset on Saturday. That is when the Eucharist was ordinarily celebrated in those earliest years – late Saturday evening. The Sabbath was over and there was no restriction on travel. At that time Sunday was still a regular work day.
As time went on and fewer Christians were Jewish, it became more convenient to make Sunday the special day for the Christian community each week, in honor of the day the Lord rose from the dead. Thus the Eucharist was commonly celebrated on Sunday mornings.
Christmas, however, was different. Very early the practice developed of celebrating the Eucharist at midnight, based on the tradition that Christ was born at midnight.
The origins of this tradition may also lie in a passage from the Book of Wisdom: “For when peaceful stillness encompassed everything and the night in its swift course was half spent, your all-powerful word leaped from heaven . . .” (18: 14-15)
- Little Blue Book, December 21