Answer: Jesus taught Nicodemus that a person was born again spiritually of water and the Holy Spirit, (verses 5 and 6).
MORE INFORMATION AND/OR OTHER SCRIPTURE REFERENCES:
John 14:26: [Jesus said,] "But the Counselor, the Holy Spirit, Whom the Father will send in My Name, will teach you all things and will remind you of everything I have said to you."
John 15:26: [Jesus said,] "When the Counselor comes, whom I will send to you from the Father, the Spirit of Truth Who goes out from the Father, He will testify about Me. And you also must testify, for you have been with Me from the beginning."
Acts 2:38-39: "Peter replied, ‘Repent and be baptized, every one of you, in the Name of Jesus Christ for the forgiveness of your sins. And you will receive the gift of the Holy Spirit. The promise is for you and your children and for all who are far off--for all whom the Lord our God will call.'"
Acts 10:45: "The circumcised believers who had come with Peter were astonished that the gift of the Holy Spirit had been poured out even on the Gentiles."
Acts 2:17-21: "‘In the last days, God says, I will pour out My Spirit on all people. Your sons and daughters will prophesy, your young men will see visions, your old men will dream dreams. Even on My servants, both men and women, I will pour out My Spirit in those days, and they will prophesy. I will show wonders in the heaven above and signs on the earth below, blood and fire and billows of smoke. The sun will be turned to darkness and the moon to blood before the coming of the great and glorious day of the Lord. And everyone who calls on the Name of the Lord will be saved.'" (Quoted from Joel 2:28-32.)
Acts 5:29-32: "Peter and the other apostles replied: ‘We must obey God rather than men! The God of our fathers raised Jesus from the dead--Whom you had killed by hanging Him on a tree. God exalted Him to His Own right hand as Prince and Savior that He might give repentance and forgiveness of sins to Israel. We are witnesses of these things, and so is the Holy Spirit, Whom God has given to those who obey Him.'"
Acts 15:6-9: "The apostles and elders met to consider this question. After much discussion, Peter got up and addressed them: ‘Brothers, you know that some time ago God made a choice among you that the Gentiles might hear from my lips the message of the Gospel and believe. God, Who knows the heart, showed that He accepted them by giving the Holy Spirit to them, just as He did to us. He made no distinction between us and them, for He purified their hearts by faith.'"
Acts 22:16: "And now what are you waiting for? Get up, be baptized and wash your sins away, calling on His Name."
Romans 5:5: "And hope does not disappoint us, because God has poured out His love into our hearts by the Holy Spirit, Whom He has given us."
1 Corinthians 6:9-11: "Do you not know that the wicked will not inherit the kingdom of God? Do not be deceived: Neither the sexually immoral nor idolaters nor adulterers nor male prostitutes nor homosexual offenders nor thieves nor the greedy nor drunkards nor slanderers nor swindlers will inherit the kingdom of God. And that is what some of you were. But you were washed, you were sanctified, you were justified in the Name of the Lord Jesus Christ and by the Spirit of our God."
Galatians 4:6-7: "Because you are sons, God sent the Spirit of His Son into our hearts, the Spirit Who calls out, ‘Abba, Father.' So you are no longer a slave, but a son; and since you are a son, God has made you also an heir."
2 Thessalonians 2:13-15: "But we ought always to thank God for you, brothers loved by the Lord, because from the beginning God chose you to be saved through the sanctifying work of the Spirit and through belief in the Truth. He called you to this through our Gospel, that you might share in the glory of our Lord Jesus Christ. So then, brothers, stand firm and hold to the teachings we passed on to you, whether by word of mouth or by letter."
Hebrews 6:4-6: "It is impossible for those who have once been enlightened, who have tasted the heavenly gift, who have shared in the Holy Spirit, who have tasted the goodness of the Word of God and the powers of the coming age, if they fall away, to be brought back to repentance, because to their loss they are crucifying the Son of God all over again and subjecting Him to public disgrace."
Hebrews 9:14: "How much more, then, will the blood of Christ, Who through the eternal Spirit offered Himself unblemished to God, cleanse our consciences from acts that lead to death, so that we may serve the living God!"
Hebrews 10:29-31: "How much more severely do you think a man deserves to be punished who has trampled the Son of God under foot, who has treated as an unholy thing the blood of the covenant that sanctified him, and who has insulted the Spirit of grace? For we know Him Who said, ‘It is Mine to avenge; I will repay,' and again, ‘The Lord will judge His people.' It is a dreadful thing to fall into the hands of the living God."
Titus 3:4-5: "But when the kindness and love of God our Savior appeared, He saved us, not because of righteous things we had done, but because of His mercy. He saved us through the washing of rebirth and renewal by the Holy Spirit..."
1 Peter 1:1-2: "Peter, an apostle of Jesus Christ, To God's elect, strangers in the world, scattered throughout Pontus, Galatia, Cappadocia, Asia and Bithynia, who have been chosen according to the foreknowledge of God the Father, through the sanctifying work of the Spirit, for obedience to Jesus Christ and sprinkling by His blood: Grace and peace be yours in abundance."
