The kingdom of heaven is like a man who sowed good seed in his field

Matthew 13

 I speak to them in parables, because seeing they do not see, and hearing they do not hear, nor do they understand.

For the hearts of this people have grown dull.
Their ears are hard of hearing,
And their eyes they have closed,
Lest they should see with their eyes and hear with their ears,
Lest they should understand with their hearts and turn,
So that I should heal them.

Therefore hear the parable of the sower:

When anyone hears the word of the kingdom, and does not understand it,  
then the wicked one comes and snatches away what was sown in his heart.

But he who received seed on the good ground is he who hears the word and understands it, who indeed bears fruit and produces.

Proverbs 2

Incline your ear to wisdom, And apply your heart to understanding;
Yes, if you cry out for discernment, And lift up your voice for understanding,
If you seek her as silver, And search for her as for hidden treasures; 
Then you will understand the fear of the LORD, And find the knowledge of God.
For the LORD gives wisdom; From His mouth come knowledge and understanding;