He told them a little story:

"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."

The first point Jesus wanted them to understand was that the seed in this story is God’s Word. Until the truth is sown into our hearts and we seek spiritual understanding, we will never be able to see God's plan.

In Hebrews 11:3, Paul explains it like this, “Through faith we understand that the worlds were framed by the word of God, so that things which are seen ... are not made of things which are seen.”