Who is the Holy Spirit?
Jesus did not want to leave His followers alone so He sent His Holy Spirit to be with them after He went to heaven.
John 14:16-17
Jesus said, I pray the Father and He will give you another Comforter that He may abide with you forever--even the Spirit of Truth whom the world cannot receive because it sees Him not, neither knows Him, but you know Him for He dwells with you and shall be in you.
Those who personally receive Christ into their hearts receive the Holy Spirit and those who reject him do not have His Spirit.
John 14:26
But the Comforter which is the Holy Ghost whom the Father will send in My Name, He shall teach you all things and bring all things to your remembrance whatsoever I have said unto you. Peace I leave with you, My peace I give unto you, not as the world gives. Let not your heart be troubled nor afraid.
The Holy Spirit will comfort you so that you never need to feel lost or lonely. The Holy Spirit will give you strength and joy and wisdom and He will guide you each day as you talk to Him personally.
Luke 12:12
The Holy Spirit will teach you and help you to speak.
Acts 16:6
The Holy Ghost warned the disciples not to go to Asia.
Romans 8:13
For as many as are led by the Spirit are the sons of God.
1 John 4:13
We know that we dwell in Him and He in us because He has given us His Spirit.