“If you love Me, you will keep My commandments: and I will ask the Father and, so that He would be with you forever, He will give you another Comforter, the Spirit of Truth, Whom the world is not able to accept, because it does not see and does not know Him: you know Him, because He remains beside you and will be inside you." (John 14:15-17) 

After three years of drawing attention to the Holy Spirit, Jesus told His Disciples: “I still have much to say to you, but you are not now able to bear it: but when that One would come, the Spirit of Truth, He will guide you in all truth.” (John 16:12-13)

For this reason Jesus told His followers to wait for the “Promise of the Father,” the “Baptism in the Holy Spirit,”  for the Father “will give you another Comforter, the Spirit of Truth, Whom the world is not able to accept, because it does not see and does not k now Him: you know Him, because He remains beside you and will be inside you. (Luke 24:49, Acts 1:4-5, John 7:37-39, 14:16-26, 20:22)

Throughout His Ministry, Jesus announced “Repent, for the Kingdom of God is near,” and Paul defined the “Kingdom of God” as “righteousness and peace and joy in the Holy Spirit.” When Jesus was asked by the Pharisees when the Kingdom of God would come, He answered them, “The Kingdom of God does not come with observation. Nor will they say, ‘Here it is!’ or ‘There it is!’ For remember, the Kingdom of God is within you.” (Mark 1:15, Romans 14:17, Luke 17:20-21, See also John 7:37-39)

Scripture makes clear “the world did not know God through its wisdom,” for it is “hidden from the wise.” It is the “Spirit of Truth,” that "the world cannot receive", that “teaches” and “reveals” the “deep things of God,” and “guides us in all truth.” (Matthew 11:25-27, - 1 Corinthians 1:18-21, - Daniel 12:10, John 14:15-25, 16:12-13)  

The Lord hides His wisdom from “fools” because of pride, envy and unbelief. Jesus confirmed this when referring to "the word of the prophet Isaiah," that "God had blinded their eyes and hardened their hearts, so that they would not see with their eyes nor understand with their heart nor would they turn back, repent, and I would heal them.’” (John 12:37-40. See also Isaiah 55:8-9, - 1 John 2:15-16)

This only would I learn of you, Received ye the Spirit by the works of the law, or by the hearing of faith? Are ye so foolish? having begun in the Spirit, are ye now made perfect by the flesh? ...[W]hen the fullness of the time had come, God sent forth His Son, born of a woman, born under the law, to redeem those who were under the law, that we might receive the adoption as sons. And because you are sons, God has sent forth the Spirit of His Son into your hearts, crying out, “Abba, Father!” Therefore you are no longer a slave but a son, and if a son, then an heir of God through Christ. --Galatians 3:2-3, 4:4-7

"But God has revealed them to us through the Spirit: for the Spirit searches all things, even the deep things of God. For who of men knows the things of a man except the spirit of the man that is in him? Thus then no one knows the things of God except the Spirit of God. And we did not take the spirit of the world but the Spirit which is from God, so that we would know the things freely given to us by God: (1 Corinthians 2:10-12) John G. Lake pointed this out saying: "We do not know God with our flesh, with our hands or with our brains. We know God with our spirit."

To "know God" is to know the "deep things of God," and to "know God," is "eternal life," as Jesus defined: "And this is eternal life, that they would know You, the only true God, and Whom You sent, Y’shua Messiah." (John 17:3) Jesus confirms having to "know God" with His warning of “I never knew you,” saying “not everyone who calls Him Lord or uses His name will enter the Kingdom of the Heavens.” (Matthew 7:21-23)

To be “taught by God,” Scripture is clear that it is the "Spirit of Truth" Who “will teach you all things,” and “all truth.” For the “natural man does not take the things of the Spirit of God: for they are foolishness to him and he is not able to know, because they are discerned spiritually.” This is a “stumbling-block” to the “lost,” and the Lord “shall destroy the wisdom of the wise and do away with the understanding of the intelligent.” Jesus said it is the “spirit that quickens, the flesh profits nothing.” (1 Corinthians 1:20-25, 2:14, Isaiah 54:13, John 6:44-45 ,63)
 
Repentance is first necessary because: “Your iniquities have separated you from your God, and your sins have hidden His face from you, so He will not hear.”  (Isaiah 59:2. See also Matthew 3:1-17, Mark 1:15, Acts 17:30-31, - 1 Kings 8:46 and Romans 3:23, John 8:10-11)

On the Day of Pentecost, after witnessing the evidence of the Holy Spirit, Peter was asked, “What shall we do? …And Peter said to them, “You must immediately repent, and each of you must immediately be immersed in the name of Y’shua Messiah, for forgiveness of your sins and you will take the gift of the Holy Spirit. For the promise is for you and for your children and for all those in far away places, whomever the Lord our God will call to Himself.” (Acts 2:1-13, 2:37-39. See also 1 John 1:8-10 and Psalm 51:1-19) 

Nicodemus when told by Jesus he must be Born Again, asked “how is it possible?” Jesus said: “Most certainly I say to you, unless someone would have been born out of water and Spirit he is not able to enter the Kingdom of God. What has been born of the flesh is flesh, and what has been born of the Spirit is spirit. Do not be astonished that I said to you, ‘It is necessary for you to be born from above’ ...to have eternal life.” (John 3:5-7, 15. See also John 1:12-13, Ephesians 2:8-9)

Adam was not a "living soul" until God "blew into his nostrils the breath of life, and man became a living being." Our spirit is “clothed with skin and flesh and knit together with bones and sinews” and God has granted us “life and loyal love, and preserves our spirit.” Jesus declared: “God is spirit, and it is necessary for those who worship Him to worship in spirit and in truth,” and Paul defined our “whole being” as “spirit, soul and body.” (Genesis 2:7, Job 10:11-13, John 4:24, - 1 Thessalonians 5:23)
 
When Elihu confronted Job and his three friends he said: “But there is a spirit in man: and the inspiration of the Almighty gives them understanding. Great men are not always wise: neither do the aged understand judgment.” When God answered Job He said: ”...Who has put wisdom in the inward parts? Or, who has given understanding to the heart?” (Job 32:8-9, 38:36)
 
Paul declared: ...“But I say this, brothers, that flesh and blood are not able to inherit the Kingdom of God, nor does corruption inherit incorruption.” ...“For those who are flesh are thinking the things of the flesh, but those according to the Spirit are thinking the things of the Spirit. For the mind-set, thoughts and purposes, of the flesh is death, but the mind-set of the Spirit is life and Peace. …For as many as are led by the Spirit of God, these are the sons of God.” ...And “if the Spirit of the One Who raised Y’shua from the dead dwells in you, the One Who raised Messiah from the dead will also make alive your mortal bodies through His Spirit because He abides within you,” as “the dust returns to the earth as it was and the spirit returns to God Who gave it.”  (1 Corinthians 15:50, Romans 8:5-14, Ecclesiastes 12:7)
 
The significance of the Holy Spirit is evident as we are instructed not to “quench” or “grieve” the Holy Spirit, “with Whom we are sealed for the Day of Redemption,” and notably, "blasphemy of the Spirit will not be forgiven." (1 Thessalonians 5:16-19, Ephesians 4:30, Matthew 12:28-32)

When Paul found disciples in Ephesus he asked: “Did you take the Holy Spirit when you believed?” And they said to him, “But in fact we did not hear whether there is a Holy Spirit.” So he said, “Then in what name were you immersed?” And they said, “In John’s immersion.” Then Paul said, “John did immerse an immersion of repentance to the people, saying that they should believe in the One Who was coming after him, that is in Y’shua.” And when they heard they were immersed in the name of the Lord Y’shua, and when Paul laid his hands upon them the Holy Spirit came upon them, and they were speaking in tongues and they were prophesying. (Acts 19:2-7)
 
(Scriptures from One New Man Bible & NKJV)
 
Learn more:

The Holy Spirit: The "Promise of the Father."  -  "I am sending the promise of My Father upon you." (Luke 24:49, Acts 1:4-5)    

Have you received the Holy Spirit since you believed? - "Immersed in the Holy Spirit" (Acts 19:2)    

Baptism of the Holy Spirit - After being "Born Again" of the Spirit Being filled with the Holy Spirit (Acts 2:1-4) 

Christian Calling: Followers of Christ - "Just as the Father sent Me, so I am sending you." (John  20:21)