'Know' in the Bible

But wilt thou know, O vain man, that faith without works is dead?

Adulteresses, know ye not that friendship with the world is enmity with God? Whoever therefore is minded to be the friend of the world is constituted enemy of God.

ye who do not know what will be on the morrow, (for what is your life? It is even a vapour, appearing for a little while, and then disappearing,)

let him know that he that brings back a sinner from the error of his way shall save a soul from death and shall cover a multitude of sins.