5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the Kingdom of God.
6 That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
7 Marvel not that I said unto thee, Ye must be born again.
8 The wind bloweth where it wishes, and thou hearest the sound thereof, but can not tell whence it comes, and whither it goes: so is every one that is born of the Spirit.
Be born of water is water baptism, repentance
Be born of spirit is listening to the voice of God.
The flesh cannot.
You need to know the voice of God: "My sheep hear my voice" he says.
The voice of God is the Holy Spirit.
Jesus defines it a the sound of the wind. Most of the time the wind makes no noise, it is very subtle and you need to calm down, stay in a silent area to hear it. You will see trees move and hear their leaves before you hear the wind. Fruitful Christians are trees. Read Scriptures.
Sometimes the wind is very loud, and then you have no excuse, do what God told you to do, and as fast as possible.
Jesus says that you won't be able to tell where the wind goes, you can't see the wind and it's path, only the consequences. That's the faith of the saints, to obey to the Holy Spirit without asking why.
The Holy Spirit will not force you to do anything, with God you always have your free will.
God want us to be fruitful, through trials we produce more fruits:
1 I am the true vine, and my Father is the husbandman.
2 Every branch in me that beareth not fruit he taketh away: and every branch that beareth fruit, he purgeth it, that it may bring forth more fruit.
Here are Fruits of the Spirit:
22 But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith,
23 Meekness, temperance: against such there is no law.
You can have three types of thoughts: your own thoughts, the Holy Spirit, and satans temptations.
Be sure to recognize who is who. "Test every spirit" as John said.
The Holy Spirit brings gifts, Paul talks about it, 1 Corinthians 12:
Wisdom, knowledge, faith, healing, miracles, prophecy, discernment, tongues, interpretation of tongues.
Recompense is in heaven, but the Kingdom has already come. Enter the Kingdom today, don't wait for it to come at you.