The New Testament doesn't spend a great deal of time explicitly addressing the question of the divinity of the Holy Spirit, unlike the divinity or the deity of the Son, where there's a great deal of attention to that he is the Creator, that he is sent from the Father, etc. The Holy Spirit doesn't get that same kind of attention. But I think there's a compelling case to be made from the way the three persons of the Godhead are mentioned, the way they appear together in the baptism of Jesus, in the presentation at the temple and those kind of events. But primarily, it's because of the way Jesus talks about the Spirit, that in the Upper Room Discourse he says, "I will ask the Father; he will send another Comforter who you already know because he is like me, and he will be with you; he will be in you." But the central, the pivotal text is in Acts chapter 5 where, in the story of Ananias and Sapphira when they lied to the apostles and claimed that they had received a certain sum of money for their house, for their property, and they had received much more than that. When Peter rebukes them Peter says, "You have lied to the Holy Spirit." And a little bit later in the same discourse, "You have not lied to man; you have lied to God." So, to lie to the Holy Spirit is to lie to God.