We hold our common assembly on Sunday because it is the first day of the week, the day on which God put darkness and chaos to flight and created the world, and because on that same day our savior Jesus Christ rose from the dead. For he was crucified on Friday and on Sunday he appeared to his apostles and disciples and taught them the things that we have passed on for your consideration.
— St. Justin Martyr, writing in the middle of the 2nd century A.D.
(excerpted from today’s Office of Readings)
See also: A day of grace and rest from work… (## 2184-2188)