So in 54/53 hours I will be flying off to New York. Not that I'm counting or anything.

And of course I'm excited about that. Its the Big Apple, the Big Country.

Its all bigger over there, I'm led believe. Its all better, its all shinier. And I shall see in a few days whether that is true. I fully expect that this time next week I shall be sat in front of the biggest Big Mac I've ever seen, with a bucket full of Coke and a box of fries the size of my head. I expect to come back supersized. Because of course if there’s one thing that America teaches us, it is that bigger is better, and biggest is best.

And at first sight, that seems to be the message of our gospel reading – a collection of Jesus parables that Matthew has brought together. The kingdom is like a tiny mustard seed growing into a great tree. Like a pearl or treasure worth more than all others, like yeast, growing and spreading throughout the dough.

Its all bigger, all better, all shinier over there in the Kingdom of God.

And yet. You know by now I'm sure, Jesus parables are rarely that simple. He takes a strange delight in constructing wonky stories and odd images.

The stories of the pearl and the treasure are both fairly simple exaggerations – imagine you found one object more valuable, more expensive, than anything else – wouldn't you give up everything to possess it. I stall find this out next week incidentally since Laura intends to buy a pair of Jimmy Choo shoes, and given that I've driven 3 cars that cost less money than a pair of those shoes costs, I may return from holiday with out less kidney than I went out with, having flogged the other one off to pay for footwear, but I digress.

Both of those simple images though, the treasure and the pearl, are not quite so straightforward though, treasure laws then as now mean that as soon as you unearth the horde, the government and whoever else is going to start circling, looking for its share. And the merchant who sells all their stock to buy something they are not willing to part with faces a difficult future himself. Both these parables, while they seem to speak of a great joy in discovering the hidden activity of God, also speak of the seeds of conflict and tension and difficult decisions to be made.

Perhaps the best known of the images Jesus uses though is the mustard seed. Maybe you are used to the idea of the smallest of seeds becoming the largest of plants and like me had never thought to look up what a mustard tree is actually like. Well yesterday I did just that. Google is your friend on these matters. And it turns out that really there is no such thing as a mustard tree. There are mustard plants, that look a bit like oilseed, flowering plants a few feet high. But no trees

Now its true that left in its wild and uncultivated state, black mustard can grow up to 9 feet high but really its a bush not a tree. Greatest of shrubs is the title Jesus gives it, a title not without irony.

It can grow to a reasonable size, but is a scruffy and unappealing plant. A big spiky gangly thing, like a big gorse bush. Not ideal bird sheltering material. It is not that Jesus didn't have other plants available to draw upon. The classic symbol for Israel was the majestic cedars of Lebanon – tall, straight, elegant and towering trees. Even the fig tree or sycamore, or an olive. If bigger is better, he certainly could have thought bigger than this.

Instead we find Jesus messing with images, teaching a message and calling it into question at the same time. Both building the kingdom up but also recognising its subversive character.

And its not that plants were different in his day either. Pliny the Elder, in his Natural History (published around AD 78 the same sort of time Matthew was writing his gospel,) says that "mustard… is extremely beneficial for the health. It grows entirely wild, though it is improved by being transplanted: but on the other hand when it has once been sown it is scarcely possible to get the place free of it, as the seed when it falls germinates at once."[10]

Mustard then was regarded as a virulent weed. Like the bindweed taking over the vicarage hedge. Once its in there, getting it shifted is virtually impossible.

It seems that although Jesus is making the more well known point about a large movement growing out of the small seed of his teaching, the vision of the tree of life that springs up from that seed is not the symbol of the great empire, the noble towering tree in the heart of the forest. It is rather a stubborn patch of scrubby growth, giving haven to the crows and the other vermin. Or if you are a monty python fan, the church is a shrubbery, only slightly higher and to the left of the other shrubbery – never mind.

It is probably no coincidence that Matthew continues the story immediately after these parables with the story of Jesus being rejected in his own home town and then records the first victim in the Kingdom of Heaven as John the Baptist is executed for standing up to Herod.

The kingdom will grow, but only because of the stubborn tenacity of its subjects, in the face of the efforts of much more powerful trees to overshadow it.

It is similar when we turn to the Yeast – I have vague memories that when I was a child my mother tried to grow her own yeast in the airing cupboard under the stairs only to underestimate just how quickly the stuff grows and ending up creating something like a bad special effect from an old B movie as this bubbling brown blob threatened to engulf all of our towels.

Yeast will certainly do as an example of exponential growth. In fact Jesus describes making 4 measures of dough – that is about 45 kilos of bread – or 100 pounds if you prefer old money. Either way its going to give you indigestion. Its a big image again.

But again it is more subversive than that. For Jews, because of the use of unleavened bread at passover, yeast had come to take on a negative connotation. Jesus himself plays on this when he says “beware the yeast of the Pharisee's and Herod”. Today orthodox Jews will scour the house before passover to remove every crumb that might contain yeast – even checking between every page of every book in the house. Its a symbol of rejecting the yeast, the leaven of corruption and wickedness in favour of the unleavened bread of sincerity and truth – to quote St Paul.

Yeast is a sign of corruption. Today probably thought of as less of a baking product and more as a cause of unpleasant infections that are difficult to shift.

The parable of the athletes foot, with the kingdom of God getting in between the toes of the world – there's an idea for the next edition of the bible.

Yes the yeast is a sign of the bigness of the kingdom. But again it is subversive and slightly uncomfortable. Big yes, but not in the way you might think.

I don't know if bigger really is better. Ask me in 3 weeks. But these parables of the large and the great are not about the bigness of the church or of God at all. They speak of a God is at work in people, events, situations (mustard seeds) we regard as insignificant and tiny. God's actions may have results wildly beyond our expectations.

But God is also at work in people, events, situations widely regarded as leaven, as subversive of the status quo and counter to standards of worldly success. They are images of the insidious and subversive nature of God's presence, and so the insidious and subversive resistance movement that is his church. It is the treasure that will bankrupt the merchant, the yeast that will infect the whole batch, the weed that will not be rooted out.

He who has ears, let him hear.