God exists as a unity. There is only one God. As Ephesians 4:4-6 says, there is one Spirit and there is one faith in one Lord who is our one God. The Bible never teaches that there is more than one God.
But God is not a simple unity like one rock or one grain of sand. He is a complex being, and He is presented that way. He is revealed as having three centers of unique personality, but in essence is one God. John 1:1-3 gives a description of this unity of Jesus and the Father. The Word was with God and, at the same time, the Word was God. When we speak of the essential nature of the Word, He is God. The Word was also with God. The Word can leave that relationship to become man: to become Jesus. Jesus is God’s Word that became flesh. Yet the Word is still God. This is a mystery that we don’t understand to its fullest extent, but scripture is clear that there is one God.
So the Holy Spirit is not a separate God, not a third God, but He is a unique personality. The Holy Spirit is not an “it,” but a Somebody. He is not an impersonal force or just an expression of power, but a person of the Trinity.
The Holy Spirit has intellect. In 1 Corinthians 2:9-16, we see that God reveals things through the Holy Spirit. The Spirit searches all things, even the thoughts of God. He knows God’s thoughts. If the Holy Spirit knows something, He must have intellect.
The Holy Spirit has emotions and sensibility. The Holy spirit can be grieved and He can love. Ephesians 4:30 warns us not to grieve the Holy Spirit. In Romans 15:30, Paul appeals to us by Jesus and the love of the Holy Spirit separately.
The Holy Spirit has a will. He can choose to give as He wills. In 1 Corinthians 12:11 the Holy Spirit apportions His gifts as He determines. He is able to make a determination and choose.
The Holy Spirit is able to teach, remind and bear witness. In John 14:25-26, Jesus tells His disciples that when the Holy Spirit comes, He will teach them all things and remind them of what Jesus taught while He was with them. In John 15:26, Jesus teaches that the Holy Spirit will bear a true witness about Him. He will teach, explain, and testify about the truth of Jesus Christ and God’s Word.
The Holy Spirit calls people, directs them, and gives them a special purpose. In Acts 13:2-4, the Holy Spirit calls Barnabas and Paul, and He gives them a special work to perform. When people are called to the mission field or service, it is done by the Holy Spirit. The Holy Spirit directed Philip in Acts 8:2...