As discussed in Part 1, God is a unity, but not a simple unity.  He is a complex being.  The Holy Spirit is not a separate God, but a member of a unified trinity who has a unique personality and intellect while still being unified with God.

In the Old Testament, the Holy Spirit lived with the people of God and indwelling only a chosen few.  In the New Testament, after Pentecost in Acts 2, the Holy Spirit lives in all believers.  He is the seal of our redemption.

The Holy Spirit accomplished the work of creating the incarnation.  In Luke 1:35, the angel told Mary that the Holy Spirit would come upon her, and so her child would be the Son of God.  In Matthew 1:20, the angel told Joseph that Mary's child was conceived by the Holy Spirit.

Jesus' entire life was intimately related to the Holy Spirit.  Matthew 12:28 says that He was empowered by the Holy Spirit to cast out demons.  After His time of fasting in the wilderness, Luke 4:15 says that Jesus returned in the power of the Spirit to Galilee.  In Luke 4:17-22, Jesus reads from Isaiah to demonstrate that He had been anointed by the Holy Spirit to preach good news.  In Acts 10:37-38, Peter is preaching in the home of Cornelius and reminds them of Jesus' ministry, and how He was anointed by the Holy Spirit.

The Holy Spirit is also intimately related to our salvation.  Jesus teaches Nicodemus in John 3 that each person must be born of water and spirit to see the kingdom of God, and it is Spirit that gives birth to spirit.  The Holy Spirit accomplishes our salvation, working in us to produce our new birth.  Paul teaches in Titus 3:4-6 that we are saved by the washing and renewal of the Holy Spirit.  The Holy Spirit cleanses us and washes us.  He is poured out on us by Jesus Christ.

The Holy Spirit Himself is a gift to believers.  Jesus taught this in John 7:37-39 as he spoke of rivers of living water for those that come to him.  In Acts 11:15-17, Peter tells the church in Jerusalem of what occurred at the home of Cornelius.  He tells of being reminded of Jesus teaching that they would be baptized by the Holy Spirit and testified that the Holy Spirit had come onto the Gentiles just as it had on the Apostles at Pentecost.  Because of their salvation, the Holy Spirit indwells all believers.  Paul also teaches in Romans 5:5 that the Holy Spirit has been given to us.

The Holy Spirit gives gifts to the church,