John 14:16-17

John 14:16-17. That he may abide with you for ever;Eeven the Spirit of truth whom the world cannot receive because it seeth him not, neither knoweth him; but ye know him; for he dwelleth with you, and shall be in you.

Worldly men are not cognizant of the existence of the Holy Spirit. They do not believe in him; they say that there may or may not be such a Divine Being in the world as the Holy Spirit, but they have never come across his path. This then is one of the tests of true believers, the twice-born, they have received a new nature which enables them to recognize the existence of the Spirit of God and to feel the influence of his work: "Ye know him: for he dwelleth with you, and shall be in you."