Answer
Not every passage that talks about the Spirit of God identifies the Spirit as a distinct person, but you do have explicitly Trinitarian passages. For instance, Matthew chapter 28, baptizing in the name of the Father and of the Son and of the Holy Spirit, and then you have other passages like in 2 Corinthians 13 and so on that mention the Father, the Son and the Holy Spirit. Also, in John chapters 14 through 16 we read about the Spirit doing things that only a person would do. For example, Jesus says that he will send another advocate like himself, the Holy Spirit, and the Spirit goes on to prosecute the world concerning sin and righteousness and judgment, just like Jesus did. The Spirit is a witness just like we are witnesses, and so on. So, the Spirit is identified as a distinct person in a number of passages.
Answer by Dr. Craig S. Keener
Dr. Craig S. Keener is the F.M. and Ada Thompson Chair of Biblical Studies at Asbury Theological Seminary.