Someone Asked Who Is The Holy Spirit & What Is the Holy Spirit Function?

The Holy Spirit is like the wind, you cannot see it but you feel it move. He's driving us forth.  Where does the wind blow us?  Forward in new directions!  At times I simply come short with my own words, but when I ask the Holy Spirit to help, I realize that He's the most powerful Evangelist on the face of the earth! The Holy Spirit is God's present activity in our midst. When we sense God's leading, God's challenge, or God's support or comfort, we say that it's the Holy Spirit.   The third person in the Trinity; our Counselor and Comforter. Jesus promised the Apostles that He would send the Holy Spirit after His Crucifixion and Resurrection; the Holy Spirit came on Pentecost. . Don't hold Him in when He wants to be let out!   If you feel like crying when you are praying, don't hold back the tears. When you walk with the Holy Spirit nobody can hold you back. Through the Holy Spirit you'll begin to make godly decisions.  You'll begin to meet people that God wants you to meet. Your life will take a completely different direction. He'll teach you when to speak and when to hold your tongue.  He'll teach you how to see through and tackle your problems.  When He lives in you, then you wants what He wants.  When the Holy Spirit lives in you, you lie down quietly and go to sleep. With Him in your life, nothing can catch you off balance.   Welcome the Holy Spirit into your life & into each moment and watch the Living God at work. Trying to be a Christian without the Holy Spirit won't get us very far.  Without the Holy Spirit everything remains standing still. We need the Holy Spirit!  Holy Spirit, inject us with new life in You! 
Acts 2.  The Spirit Comes At Pentecost
Matthew 3:11: The Holy Spirit Outpouring Foretold

Chapters & Scriptures that helps us truly understand the Holy Spirit.
John 3:5
Acts 10: 44-46
Acts 19:6
Luke 11:9-13
Romans 8:9