Jesus told His apostles...
"I will ask the Father, and He will give you another Helper, that He may be with you forever; the Spirit of truth, whom the world cannot receive, because it does not behold Him or know Him, but you know Him because He abides with you, and will be in you. I will not leave you as orphans; I will come to you."
The Holy Spirit is a Person equal in every way with God the Father and God the Son. He is said to be the third member of the Blessed Trinity.
The Holy Spirit bears witness of Jesus Christ and He is a Supernatural Teacher to Christians. Jesus told His disciples...
"The Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all that I said to you."9
"When He, the Spirit of truth, comes, He will guide you into all the truth; for He will not speak on His own initiative, but whatever He hears, He will speak; and He will disclose to you what is to come."
The Holy Spirit also has a role in Non-Christians as well. He convicts people's hearts of God's truth concerning how sinful we are -- needing God's forgiveness; how righteous Jesus is -- He died in our place, for our sins; and God's eventual judgment of the world and those who do not know Him. He rings in our Hearts telling us to repent and seek the Mercies of God.
Read the following Scriptural Passages to know more about the Holy Spirit: (1) Acts chapter 2 (2) John 14:16-18 (3) Matthew 28:18-20 (4) John 1:12-13; John 3:3-21 (5) 1Corinthians 3:16 (6) 1Corinthians 2:11; Romans 15:30; 1Corinthians 12:11 (7) John 15:26, 16:14 (8) 1Corinthians 2:9-14 (9) John 14:26 (10) John 16:13 (11) Galatians 5:22-23 (12) Galatians 5:25; Ephesians 5:18 (13) Romans 12; 1Corinthians 12; Ephesians 4 (14) John 16:8-11
