Who is the Holy Spirit?
The Holy Spirit is the 3rd Person of the Holy Trinity made up of God the Father, God the Son and God the Holy Spirit. Our God is One God. The Holy Spirit is presented throughout scripture both in the old and new testaments fully sharing all the attributes of Deity. He is the wonderful One that was promised to be sent to us by the Father when Jesus spoke of Him in the Gospel of John. The Holy Spirit is more than just a "force" or a "power". He is not an "it" or a "thing" but an actual Person of the Godhead. The Holy Spirit is God Himself. (Acts 5:3,4 2Corinthians 3:17)
The Holy Spirit is your closest Friend. He is not a subject to be learned but a Person to be known, One you would want to get a hold of you rather than a mere power you want to get a hold of.
Like Jesus the Person of the Holy Spirit is eternal and living. Now when I say the Holy Spirit is a person I'm not saying He has a body like you and I know it, yet, He is not without form. In one sense we become His body when He lives within us.
Go into all the world and preach the Gospel to every creature." Mark 16:15