But the comforter which is the Holy Ghost, whom the father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.

But when the comforter is come, whom I will send unto you from the father, even the spirit of Truth, which proceeded from the father, he shall testify of me

God is a spirit, and those who worship Him must worship Him in spirit and in truth.