That's the command of our Lord: You Must be Born Again! Without our being Born Again, we'll go through life never knowing ourselves, or what deep grief sin is, or who God is! There is a New Birth involved here. One that was only "physical" in nature (born once), to one that is now "Spiritual" in nature (born twice).
Luke 8:11 Now the parable is this: The seed is the word of God.
John 12:24-26 Verily, verily, I say unto you, Except a corn of wheat fall into the ground and die, it abideth alone: but if it die, it bringeth forth much fruit. He that loveth his life shall lose it; and he that hateth his life in this world shall keep it unto life eternal. If any man serve me, let him follow me; and where I am, there shall also my servant be: if any man serve me, him will my Father honour.
I'll use a caterpiller as an example of what I mean....
All the caterpiller does day and night is crawl,eat and sleep, crawl, eat and sleep. It is required to hibernate - CHANGE - into something that before was "impossible" for it to do... change into a butterfly . Until it becomes a pupae and hibernates in its shell it will never be any more than a caterpiller. The difference between the two is like night and day.
The caterpiller could only see things from his perspective, and that is to crawl and eat and sleep. The butterfly; on the other hand, is what the caterpillar set out to be. Now he has many eyes and the ability to use them, and even floats on air. What he sees and knows is something that the immature caterpiller is completely blind to: namely the butterfly now goes after flowers to stick his long, curly tongue in there and lap up sweet nectar. So, not only did the caterpillar change into a butterfly - into a brand new creature - but he also changed the way he looked at things, as if seeing them for the first time. It is at that instant when All Things Become New. I only use a caterpillar and a butterfly as being two distinct creatures of the same but radical kind....
Romans 11:33 O the depth of the riches both of the wisdom and knowledge of God! how unsearchable are his judgments, and his ways past finding out!
Matthew 13:8 But other fell into good ground, and brought forth fruit, some an hundredfold, some sixtyfold, some thirtyfold.
"Preparation"! The greatest thing that we - as Christians - do is to consider the complete text or the full word of God, and how Jesus is God in the flesh. We now have a desire to want to know more of these "Spiritual" things. Whereas the purely "physical" in nature are out to eat (have) anything they can get their hands on in this world (do you know anyone like that?). While those who are "Spiritual" (born of God) in nature tend to want to know only more of God (do you know anyone like that?).
We are not like thee others who don't really hear what God is saying, but only hear what they want to hear. We hear God, both speaking to us through His word and by the Holy Spirit, and it is these very Scriptures and words that become loud and clear to "our" understanding. (Now picure, if you will, a pupae entering the pupae or preparation stage)....
John 5:44 How can ye believe, which receive honour one of another, and seek not the honour that cometh from God only?
Romans 2:29 But he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God.
It is our job to beware of Pretenders, the phonies, those who look good on the outside but are full of dead mens bones on the inside!
They are not always easy to spot; especially for one whose heart is not completely set on being sanctified to the Truth, because although they too preach the word of God, they don't do so by the Spirit....
John 6:63 It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they are life.
2 Corinthians 3:6 Who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life.
We all MUST become like the butterfly is to the caterpiller.... "Completely Changed"! All we know is that we are Brand New Creatures made in God's HOLY Image, and we won't know exactly who we are until....
1 Corinthians 2:9-11 But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love him. But God hath revealed them unto us by his Spirit: for the Spirit searcheth all things, yea, the deep things of God. For what man knoweth the things of a man, save the spirit of man which is in him? even so the things of God knoweth no man, but the Spirit of God.
Not only is having the Spirit vital to our being Born Again, but it must be seen that without the Spirit we have no way of knowing who God is... much the same as a butterfly is to the caterpillar.
Romans 8:10-11 And if Christ be in you, the body is dead because of sin; but the Spirit is life because of righteousness. But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead shall also quicken your mortal bodies by his Spirit that dwelleth in you.
1 Corinthians 2:11-12 For what man knoweth the things of a man, save the spirit of man which is in him? even so the things of God knoweth no man, but the Spirit of God. Now we have received, not the spirit of the world, but the spirit which is of God; that we might know the things that are freely given to us of God.
It is so important to let the rest of you: YOUR MIND, be changed also. Let it be Blown Away, so to speak! Oh, you'll still use it alright, but it will have in it The Knowledge of God - The completely Other, who cannot be explained. The word of God and the Spirit are determined to Keep Us Safe while walking in this world, as long as we don't grieve Him. The reason of the Gospel is simple: That Jesus Christ shed His blood to pay for your sins. Prophecy (as you find it in Matthew 24, Revelation, etc.) is similarly easy to understand as well, IF we don't taint it with mans words and with man saying this is what that means, and visa versa. Listen to God only! He will guide you into All Truth!