"Jesus said, “This is how it is with the kingdom of God; it is as if a man were to scatter seed on the land........“To what shall we compare the kingdom of God.... It is like a mustard seed that, when it is sown in the ground, is the smallest of all the seeds on the earth. But once it is sown, it springs up and becomes the largest of plants and puts forth large branches, so that the birds of the sky can dwell in its shade.” (Mark 4: 26, 30 - 32).
Jesus Christ came to establish the Kingdom of God. He taught us to pray every day for the coming of the Kingdom. "Thy Kingdom come. Thy will be done on earth as it is in heaven." (Matthew 6: 10).
But what is the Kingdom of God? The Kingdom here on earth consists of the men and women who submit themselves to the rule and discipline of God in their hearts and minds.
In the parable of the Mustard Seed, Jesus revealed one characteristic of the Kingdom. It starts very tiny. Like a mustard seed. And it grows and grows and grows.
We get the same picture of the mystery of the Kingdom from the First Reading from Ezekiel:
"Thus says the Lord God:
I, too, will pluck from the crest of the cedar the highest branch.
From the top a tender shoot I will break off and transplant on a high, lofty mountain. On the mountain height of Israel I will plant it. It shall put forth branches and bear fruit, and become a majestic cedar.
Every small bird will nest under it,
all kinds of winged birds will dwell in the shade of its branches." (Ezekiel 17: 22 - 23).
The seed and beginning of the Kingdom of God is the Church. (CCC 541).