'First Day' in the Bible

And on the first day of unleavened bread, when they killed the passover, his disciples said to him, Where do you wish us to go and prepare to eat the passover?

And very early in the morning, on the first day of the week, they came to the tomb at the rising of the sun.

AND having arisen early on the first day of the week, he appeared first to Mary the Magdalene from whom he had cast out seven demons.