Answer: That he is God, coeternal with the Father and the Son, and that God grants him irrevocably to all who believe.

Scripture: And I will ask the Father, and he will give you another Helper, to be with you forever, even the Spirit of truth, whom the world cannot receive, because it neither sees him nor knows him. You know him, for he dwells with you and will be in you. – John 14:16-17

Source: New City Catechism – Note that this link will take you to their website on this specific question where there are commentaries offering a deeper insight into the answer offered here. Look for the icons on the top right of the page.

.