'Natural' in the Bible

who were born, not of blood [natural conception], nor of the will of the flesh [physical impulse], nor of the will of man [that of a natural father], but of God [that is, a divine and supernatural birth—they are born of God—spiritually transformed, renewed, sanctified].

You are of your father the devil, and it is your will to practice the desires [which are characteristic] of your father. He was a murderer from the beginning, and does not stand in the truth because there is no truth in him. When he lies, he speaks what is natural to him, for he is a liar and the father of lies and half-truths.

However, Jesus had spoken of his death, but they thought that He was referring to natural sleep.