'First Day' in the Bible

And on the first day of unleavened bread, when they killed the passover, his disciples said unto him, Where wilt thou that we go and prepare for thee to eat the passover?

And very early on the first day of the week, they come to the sepulchre, as the sun was rising.

Now being arisen early, on the first day of the week, he appeared first to Mary Magdalene, out of whom he had cast seven devils.