'Unless' in the Bible

He said, "How can I, unless someone explains it to me?" He begged Philip to come up and sit with him.

Some men came down from Judea and taught the brothers, "Unless you are circumcised after the custom of Moses, you can't be saved."

unless it is for this one thing that I cried standing among them, 'Concerning the resurrection of the dead I am being judged before you today!'"

Paul said to the centurion and to the soldiers, "Unless these stay in the ship, you can't be saved."