Do you want to know the mysteries of the kingdom of heaven? Believe and you will see.

Those who are “of this world” can never see the “kingdom of heaven”, much lest enter into it. Here is what Jesus said about such people:

¹⁰ And the disciples came, and said unto him, Why speakest thou unto them in parables?

¹¹ He answered and said unto them, Because it is given unto you to know the mysteries of the kingdom of heaven, but to them it is not given.

¹² For whosoever hath, to him shall be given, and he shall have more abundance: but whosoever hath not, from him shall be taken away even that he hath.

¹³ Therefore speak I to them in parables: because they seeing see not; and hearing they hear not, neither do they understand.

¹⁴ And in them is fulfilled the prophecy of Esaias, which saith, By hearing ye shall hear, and shall not understand; and seeing ye shall see, and shall not perceive:

¹⁵ For this people’s heart is waxed gross, and their ears are dull of hearing, and their eyes they have closed; lest at any time they should see with their eyes and hear with their ears, and should understand with their heart, and should be converted, and I should heal them.

—MATTHEW 13

The kingdom of this world and the kingdom of heaven are diametrically opposed. For those in this world, for those who have their minds set on earthly things, they want to see and understand things first and then they will believe. But in the kingdom of heaven, it is the exact opposite. Believe first and then you will see and understand. You must trust in the LORD and lean not on your own understanding (see Proverbs 3:5). In order to enter the kingdom of heaven, you must take the step of faith. Believe first and then you’ll see.
 

It’s like this: humans are composed of body, soul, and spirit. Your soul is made up of your mind, will, and emotions. The point of contact between God in heaven and men on earth is through a person’s spirit. But for those who are “of this world”, they are spiritually dead (not totally dead, but on life support, everyone has a flicker of God’s spirit in them). So they cannot receive revelation from God, for the line of communication is not working. So when the people who are “of this world” try to understand the supernatural world, they are using only their natural minds (their soul) and it makes no sense to them. They cannot see, nor can they hear. But once a person takes the step of faith and believes on Jesus, they become born again and their spirit comes alive and the line of communication between them and God works. So then God, who is Spirit, is able to communicate with that person’s spirit and gives revelation to that spirit. The spirit of such a man then is able to infuse the soul with the revelation it has received. Such a person is able to see God and hear from God because his spirit has been quickened and made alive in Christ.
 

So, for those wish to see before they will believe, they will continue to look and look without ever seeing. But for those who take the step of faith and believe first, they will see and they will understand because they have eyes to see with and ears to hear with. The kingdom of heaven belongs to such as these.