'First Day' in the Bible

On the first day of unleavened bread (the day when the paschal lamb was sacrificed) his disciples said to him, "Where do you want us to go and prepare for you to eat the passover?"

and very early on the first day of the week they went to the tomb, after sunrise.

(a) Now after he rose early on the first day of the week, he appeared first to Mary of Magdala out of whom he had cast seven daemons.