'First Day of the Week' in the Bible

The first day of the week early in morning Mary Magdalene, when it was yet dusky, came to the sepulchre, and found the stone was taken away from the sepulchre.

The same day at evening, being the first day of the week, the doors of the house where the disciples were, being shut, for fear of the Jews, Jesus came and stood in the midst, and said to them, peace be with you.