'First Day of the Week' in the Bible

And early on the first day of the week, while it was yet dark, Mary Magdalene came to the tomb, and saw that the stone had been taken away from the tomb.

Then, on that day, the first day of the week, when it was evening, and the doors of the house in which the disciples were assembled had been closed for fear of the Jews, Jesus came and stood in the midst, and said to them: Peace be to you.