First we have to know where the Kingdom of God is on this earth.
Luke 27:21 For indeed, the kingdom of God is within you.
Every believer of Jesus has the kingdom of God in our hearts. It is not in the church, or in a building or in a ministry. It is in the hearts of men.
So the kingdom of God is like a grain of mustard seed sowed in our hearts. Remember it is greatest amongst all herbs and can grow into a tree so that the birds of the air can come and find solace and refuge on its branches. Remember Jesus said in John 15:5, "I am the vine, you are the branches."
What is this mustard seed in our hearts?
I say to you, if you have faith as a mustard seed, you will say to this mountain, 'Move from here to there,' and it will move; and nothing will be impossible for you.'
So here it refers mustard seed to faith.
This is interesting. The Word of God says faith as a mustard seed. The Word of God never says faith like the small size of a mustard seed, which is often preached. Therefoe faith is like the total characteristics of the mustard seed. Size is only one small part. If we preach on size alone, then we miss the whole point.
The total characteristics of the mustard seed can encompass the following:
1) Althought smallest seed of all herb plants, it can grow the biggest.
2) Its branches give birds of the air a resting place.
3) Mustard is an easy crop to grow.
4) Mustard greens are an excellent source of vitamins A, B and C.
So when we receive Jesus the faith in our hearts as a mustard seed can easily grow into a spiritual giant. And the birds of the air (the people who are directionless in their spiritual life who come across our path) can find our testimony and sharing of Christ that they will come to a place of living spiritual life.
Faith comes by hearing and hearing the Word of God. It is really our close relationship with Christ (praying, reading and hearing the Word) that easily makes our faith grow, even though we are a nobody, because that faith will grow very fast and very big in next to no time so that we can be a blesssing to others. And nothing will be impossible because Jesus is behind every miracle.
Remember you can be highly used by God to reach out to the troubled and unsaved.