Luke 13:18-21 Jesus uses two parables here to describe the "kingdom of God". In the first He compares it to a mustard seed that was thrown into a garden and grew into a large tree. In the second He compares it to leaven hidden in the meal until the whole thing was leavened.
The Kingdom of God is the central message of the Gospel. The prayer that Jesus taught His disciples begins with these requests.. that God's name would be hallowed, that His Kingdom would come, and that His will would be done. Without the fear of God.. knowing Who He is and the greatness of His Name and the Power of His Grace we cannot know His Kingdom that will come. The Kingdom of God is more than a place.. it is a recognition of the sovereignty of God who created all things, who reigns over all of His creation, and Who has sent His Son to redeem and restore His Kingdom on earth as it is in heaven,.. And this is His will.. that we seek His Kingdom and His righteousness above all else.
So, how is this great and wonderful Kingdom like a mustard seed or leaven. Both of these things are small.. practically unseen.. but they have a powerful effect on the earth. Jesus tells us that the mustard seed will grow into a tree that provides a place for the "birds of the air". He says that the leaven will affect the whole lump of dough. These things will act as God created them to be and the Kingdom will also affect the whole earth just as He has planned and purposed. When we pray for His Kingdom to come we are praying for His will to be done on earth according to His plans and purpose and this will glorify His holy name. We are asking that others will come to know the Greatness of our God and the Wonder of His reign over all He has created... that they will be made new in the salvation that comes in believing in Jesus Christ .
How much more vital than those things that the Pharisees worried about.. work on the Sabbath, healing, eating without washing, etc. God's priority is His Kingdom! He wants us to belong to Him, to seek Him, to know Him and to help others to seek Him too.
Jesus is going to keep teaching about God's kingdom during these last days and weeks before He reaches Jerusalem and gives Himself up so that we can belong in that Glorious Kingdom for eternity. We must allow the message of the gospel to grow like a mustard seed and become a place with others will find Jesus. We must allow His Word to fill us and expand throughout our land and around the world so that all will see that the Kingdom has come in Jesus Christ and that He is coming again to take us with Him forever and ever, Amen.
Father in heaven, we hallow Your name and we pray that You will be exalted in all the earth and in every nation . We pray that Your Kingdom will be made known and that many more will come to You and bow before You. We pray that in all things Your plans and purposes will be done. In the name of Jesus we ask this, Amen.