Mark 16:2
Very early on the first day of the week, just after sunrise, they were on their way to the tomb — the first day of the week (the day after the Sabbath, Sunday) is the day the resurrection narrative locates the empty tomb. Very early, just after sunrise: the darkness is barely finished when they arrive — the first light of the new creation's day. The first-day language will become the basis for Sunday worship in the early church: the Lord's Day, the day of resurrection.