The Holy Spirit is the most mysterious member of the Trinity, which includes God the Father, God the Son (Jesus Christ), and God the Spirit (or the Holy Spirit). Many struggle with the idea of God being three persons, yet one. Quite honestly, we will never fully grasp the concept this side of heaven.
Some, however, have wrongly thought of the Holy Spirit as more of an "it" than a "him." That is probably due in part to biblical descriptions of him as being like the wind or coming upon Jesus in the form of a dove, among other comparisons. Yet these descriptions must be balanced with the descriptions of the other members of the Trinity. For instance, Jesus referred to Himself as "the bread of life" and "the good shepherd." In the same way, God the Father is referred to as "a refuge" and "a consuming fire." Does this mean that Jesus is a loaf of bread or a sheep farmer, or that the Father is a pile of rocks or a blasting furnace? Of course not! These are simply metaphors used in Scripture to help communicate God's character.
Likewise, the unique description attributed to the Holy Spirit do not imply that the Holy Spirit is merely some "force" or "power." Jesus said this about the Holy Spirit: "When the Spirit of truth comes, He will guide you into all truth... He will tell you about the future" (John 16:13). Note the use of the pronoun He. The Holy Spirit has a distinct personality, and He also has specific work that He wants to do in our lives a followers of Jesus Christ. Explore what the Bible says about Him.
1. Who does the Holy Spirit help? The Holy Spirit strenghtens and empowers followers of Christ (Acts 2: 1-40).
2. How does the Holy Spirit work with the Father and the Son? The Holy Spirit works alongside God the Father and Jesus, God's Son, to make our lives pleasing to God (1 Peter 1:2).
3. Why does God us the Holy Spirit? The Holy Spirit's presence in our lives is God's mark of ownership (Ephesians 1:13-14).
4. How does the Holy Spirit work in our lives? The Holy Spirit draws us to Christ, enters our life at conversion, and empowers us as we allow Him to work in our life (John 14:15-17).
5. When can the Holy Spirit be sinned against? There are six specific ways we can sin against the Holy Spirit (Acts 5:1-10).
6. Why do Christians need the Holy Spirit? Living the Christian life is impossible without the Holy Spirit's help (Galatians 5:16-26).
I have a response to each one of these, if you want, but I figured that the post was long enough, and if you wanted to know more about it, just ask.