Doctrine
"Howbeit when he, the Spirit of truth, is come, he will guide you into all truth."
John 16:13
Many people speak of the Spirit of God as if He were a force, an influence, or a feeling. The Bible speaks of Him as a Person — a divine Person, co-equal and co-eternal with the Father and the Son. He is the Holy Ghost, the Spirit of the living God, and no soul is saved, and no believer stands, without His work.
A force cannot speak, teach, grieve, or be lied to. The Holy Ghost does and can. He speaks and sends; He teaches and brings to remembrance; He can be grieved by our sin; and to lie to Him is to lie to God.
"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." (John 14:26)
"Why hath Satan filled thine heart to lie to the Holy Ghost?... thou hast not lied unto men, but unto God." (Acts 5:3-4)
He is the third Person of the Godhead — one with the Father and the Word.
"For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one." (1 John 5:7)
The Bible is not the product of human genius. Holy men wrote as they were carried along by the Holy Ghost, so that every word they set down was the Word of God.
"For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost." (2 Peter 1:21)
No preacher can awaken a dead soul; that is the Spirit's work. He reproves the world of sin, of righteousness, and of judgment, and when a sinner believes on the Lord Jesus Christ, it is the Holy Ghost who gives him the new birth — born not of flesh, but of the Spirit.
"And when he is come, he will reprove the world of sin, and of righteousness, and of judgment." (John 16:8)
"Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God." (John 3:5)
The moment you trust the Lord Jesus Christ, the Holy Ghost takes up residence in you — not visiting occasionally, but dwelling permanently — and He seals you unto the day of redemption. A seal is God's own mark of ownership and security: what He seals, no one can unseal.
"In whom also after that ye believed, ye were sealed with that holy Spirit of promise, which is the earnest of our inheritance." (Ephesians 1:13-14)
"Know ye not that your body is the temple of the Holy Ghost which is in you?" (1 Corinthians 6:19)
He bears witness within the believer that he is a child of God; He guides into all truth as we read the Word He gave; He helps our weakness in prayer; and He produces in us fruit that no human effort could grow — love, joy, peace, longsuffering, gentleness, goodness, faith.
"The Spirit itself beareth witness with our spirit, that we are the children of God." (Romans 8:16)
He does all of this while never drawing attention to Himself, for His delight is to glorify the Lord Jesus Christ.
"He shall glorify me: for he shall receive of mine, and shall shew it unto you." (John 16:14)
"The grace of the Lord Jesus Christ, and the love of God, and the communion of the Holy Ghost, be with you all. Amen."2 Corinthians 13:14