A Mustard Seed?.....really?

Today in Luke 13:18-21, I read;

Then he said, "What is the kingdom of God like? To what can I compare it?
It is like a mustard seed that a person took and planted in the garden. When it was fully grown, it became a large bush and 'the birds of the sky dwelt in its branches.'"

Of all the things that come to mind when I envision the kingdom of God, I would never think of comparing it to a mustard seed. At first I was trying to picture what a mustard seed looks like and forgot that in my spice rack I have a little container of mustard seeds which I have probably used once or twice in a recipe (link to recipe below). Even after having remembered what it looks like and tastes like, I would never compare it to the kingdom of God - but who am I to know what the kingdom of God is like?

If we have never seen God how can we fathom what the kingdom of God is like? It is through faith that we love God and in hope that we will attain this kingdom but a mustard seed does nothing to  strengthen my faith.

It is St. Ambrose, one of the doctors of the church, who helps me understand what is meant by this comparison.  "Another passage that refers to a mustard seed comes to mind where it is compared to faith, when the Lord says: «If you had faith like a mustard seed you would say to this mountain: «Cast yourself into the sea» ((cf. Mt 17,20; Mk 11,23)... So if the Kingdom of heaven is like a mustard seed and faith is like a mustard seed, then it goes without saying that faith is the Kingdom of heaven and the Kingdom of heaven is faith. To possess faith is to possess the Kingdom... That is why Peter, whose faith was genuine, was given the keys of the Kingdom of heaven that he might likewise open it up to others (Mt 16,19)."

Henry David Thoreau said, "The smallest seed of faith is better than the largest fruit of happiness"

I guess I was envisioning this large fruit of happiness as the kingdom of God which has it's birth in the smallest seed of faith.

Jesus said,"Verily I say unto you, none will be saved unless they believe in my cross. But those who have believed in my cross, theirs is the kingdom of God."

Lord, guide my feet so that the smallest steps I take will all be for your glory.

http://www.myrecipes.com/recipe/mustard-seed-chive-vinaigrette-10000001714576/