'First Day' in the Bible

And on the first day of unleavened bread, when they killed the Passover, his disciples say to him, Where do thou want, after going, we should prepare that thou may eat the Passover?

And very much early morning on the first day of the week, they come near to the sepulcher when the sun was risen.

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