The Mystery of the Kingdom is the Power of the Word as Seed.
Jesus declared that our reception of the Word or rejection of it determines everything that is important in our Lives here and the hereafter.
The degree to which we respond to the Word determines it's effectiveness. The more we Respect it and use it, the more Power is released through the Word on our behalf.
Not responding to the Word has a negative effect on our Lives - we Lose even that which we had.
When the Word is Sown as Seed on Good Ground it Will bring forth Increase.
After Jesus taught the Disciples about the Power of Words he rebuked the wind to demonstrate what He had taught.
Then Jesus rebuked the Disciples for not Receiving what He had taught them about the Mystery of the Kingdom.
God Spoke the Universe into existence.
God gave the Prophets His Words.
Jesus became the Word incarnate.
Grace was provided when God said He would remember our Sins and Iniquities no more.
We are Saved by Believing on Christ Jesus and Confessing Him with our Mouths.
We are Healed by the Word of God.
We are to Preach the Gospel.
We are to Speak to the mountain.
In summary, the Mystery of the Kingdom is the unlimited Power of Words when spoken in Faith.