One question people often have regarding Jesus’ parables—and in fact it’s one that was asked in Jesus’ day too—is “why speak in riddles at all? Why not just come right out and say what you mean!”
The answer, from the Lord’s own lips is…
Therefore speak I to them in parables: because they seeing see not; and hearing they hear not, neither do they understand. 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: 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.
In other words, Jesus knew that many of the people He preached to were stubborn, set in their ways, resistant to change, and more likely to shoot the messenger than give the message a fair shake.
Nevertheless, the people needed to hear certain things, so how do you preach to a people that don’t want to listen to those things?
At the same time, the people of Judea and Galilee were grossly, spiritually underfed. The deep truths of the Kingdom and of the Messiah’s Ministry were so far removed from where their hearts and minds were, Jesus would have had better luck preaching to children than those adults.
Nevertheless, the people needed to hear certain things, so how do you preach to a people that aren’t emotionally or intellectually equipped to process those things?
Faced with those two problems (stubborn and spiritually-stunted), you can see why Jesus couldn’t just come out and say “the Kingdom of Heaven is not a restored Jerusalem, home to Jews and Jews only. The Messiah-King is not going to lead a violent revolution. The citizens of the Kingdom are not violent warriors with blood-stained swords. The Kingdom is spiritual and built for all, the King is meek, the members fight against spiritual wickedness, not physical.”
How do you convey that message to a stubborn and spiritually-stunted people? You say…
“once upon a time, there was a boy who ran away from home…”
“once upon a time, there was a great wedding, and everyone was invited…”
“once upon a time, there was a servant who was forgiven of a great debt, but also had a friend who owed him a small amount…”
What did Jesus do? He told the Truth, covered in a story the way peanut butter is covered in chocolate.
That’s why He’s the Master Teacher.