Despite that cautionary tale, I will risk another of Paul's rhetorical questions: `Who is sufficient for these things?' (2 Corinthians 2.16).

A few verses later he answers his own question: `Not that we are sufficient of ourselves... our sufficiency is from God'. First, the question. There is no verb in the original. There didn't need to be. Whether Paul had written 'Who has been sufficient?' 'Who is sufficient?' or 'Who will ever be sufficient?' the answer would have been the same: `No one, but no one' ­ for this simple reason: the God of the Bible is for ever asking the impossible of people. Through Scripture from start to finish there runs the same theme:
Vocation Impossible. God seems to make a habit of asking the impossible of people: sends them where they don't want to go, gives them messages they don't want to take, or no one wants to hear, propels them into situations with the odds stacked against...

No wonder, faced with 'vocation impossible', people objected. Abraham: 'I'm too old'; Jeremiah, (as we heard): `I'm too young'; Jonah: `I've a boat to catch'; Moses: 'Unaccustomed as I am to public speaking'. And they weren't just being modest. Harry McKeating reckons Jeremiah, since he wasn't married, must have been 'a young teenager'. And, as if under-age preaching were not bad enough, God says to this wilting, stammering teenager, 'You are to go wherever I send you, and say whatever I tell you to say'.

Vocation impossible! Who can possibly be sufficient for these things? Is that not the story of our life? I mean, the story of LPMA's life? For 156 years, God has been asking ordinary women and men to do the impossible. As Jesus does every time He puts His hand on someone's shoulder, and says, 'I want you to be my disciple. Follow Me'.

Vocation impossible! But, as preachers, we have always known this ­ or, at least, we better had. It doesn't matter how long we've been on the plan; it's as impossible now, as impossible every time we ascend the steps of a pulpit, as it was when we first went on note.

Of course, it could be easier. As the years go by, we get a good stock of sermons for a rainy day. When in doubt, we can always wheel out a tried and tested joke or illustration, (provided we can remember where we've told it before). We can do all that, but in preaching, practice never makes perfect. It's as impossible as the day we started, for this reason: we are called to communicate life-giving truth. Like Jeremiah, our task is to bring people the Word of the Lord. That can't come just 'off the top of our heads'. It has to come from so deep inside ourselves, that, as someone once put it, it 'might almost be from somewhere else'. Indeed, it is. It is simply not in our gift.

We are called to preach Christ, and we may say all the right words, we may even touch people's emotions, but only God, through, or even despite what we say, can touch hearts and lives. We are not sufficient for these things. But God is. The Greek Old Testament, which Paul would have known well, calls God 'The Sufficient One'.

Years ago I read Richard Wurmbrandt's moving account of his 14 years imprisonment and torture, as a Christian pastor, in communist Romania. He suffered terribly for his faith. And yet, when a fellow prisoner one day said to him, 'Your God asks the impossible', Wurmbrandt could still reply 'God always gives what He demands'.

The full biblical 'template' of vocation stories runs like this: God asks the impossible of us; always, always; like Jeremiah, we object; but then the promise: 'I shall be with you'. The promise of the One who, unlike us, is sufficient.

Vocation impossible. Yes, we know it every time we step into a pulpit. How can we change hearts and lives? But the God of the Bible, who makes a habit of asking the impossible of His people, is a God of grace. And as my New Testament mentor, the late Kenneth Grayston, says so gloriously and simply in one of his last books: 'Grace is that power which enables us to be and do what otherwise we would not be able to be and do.'

LPMA members will have experienced that down the years again and again. God has blessed our inadequate efforts. The word we were given proved to be just the right word. Someone said `Thank you' after the service in a way that meant they had been 'fed'. We can never, ever presume. But what Jesus once said, to bemused, despairing disciples about following Him, we may apply to our vocation as preachers: 'For mortals it is impossible, but not for God' ­ not for the Sufficient One ­ 'for God all things are possible'.

But now another impossibility hoves into view. The American New Testament scholar, John Knox, once wrote that, even more important than preparing our sermons, is the preparation of ourselves. Jeremiah knew - to his great discomfort - and Paul even more so, that the message and the messenger are inseparable. The messenger must embody his message. The preacher must live the Word she has been given. And this is the second impossibility: transformation impossible.

St Paul, of course, isn't every preacher's favourite cup of tea. I vividly remember an Anglican lay reader, a woman, reading from Colossians the passage which includes 'Wives obey your husbands', and announcing at the end, with a twinkle in her eye, 'This is not the Word of the Lord'!

Even more difficult, in a different way, is the picture of the Christian life, according to Paul. It is cruciform: `Always, in our person, we bear the dying of Jesus, that also, in our own person, there may be seen the life of Jesus...'

A cruciform existence! A life centred utterly on the cross and resurrection of Jesus. `Who is sufficient for these things?' Here is the second utterly impossible thing: the messenger lives, embodies the message. Is this not 'transformation impossible'?

Where does the preparation of ourselves to preach begin? When did it begin? God's preparation of Jeremiah began even before he was born! And to the task of preaching do we not bring all we have ever been? Isn't every fibre of our being his raw material? So the preparation of ourselves to preach began ­ when? At our conversion? In our childhood or youth? At least that, since 'goodness and mercy have followed us all the days of our lives'. Again, down the many years of LPMA's history, there will have been countless testimonies to grace: that power of God enabling people to be what otherwise they could not be!

The message and the messenger belong inseparably together. The vocation commits us the transformation. But how easily the messenger belies the message! I remember how, in my shortlived teaching career, I once wrote sternly in one little girl's exercise book 'Your writing must improve'. 'Please sir' she said, when she got her book, 'Please sir, what does this say? I can't read your writing'.

Conversely, listen to this testimony to a relative of one of our greatest prime ministers: 'Living with him, it was easy to have faith'. If only people will say, 'Listening to him/her preach, it's easy to have faith!' because they can tell: the message and the messenger are one. 'We proclaim Christ', said Paul, 'Christ nailed to the cross', and though we do not preach the cross as such every Sunday, the cross is never absent, in this sense: we do not preach ourselves. Dr Sangster, the great Methodist preacher, suggested this rule of thumb: for every reference we make to ourselves, let there be at least seven to Him.

How, otherwise, will they hear the Word, if we get in the way? Unless we deepen our understanding of ourselves, deepen our integrity, and, above all, our capacity to love, how shall we have anything to give? All we shall communicate will be our own preoccupations, prejudices and ideas.

Isn't such a transformation impossible? How could an organization born in Methodism ever ask that! I once heard a preacher say that God will take you as far in the Christian life as you are prepared to go. And in our tradition we have never set limits to what God can accomplish in a human life. Methodists are Christian optimists! Down the years we have sung 'Finish then Thy new creation'. Since our earliest years we have prayed `Perfect me in love', 'Perfect holiness in me'. Methodists, of all people, believe the impossible can happen! God can kindle a flame of sacred love even in our hearts.

Have we stopped believing this? I hope and pray not. Or are we to admit that our Christian life, our prayers and our preaching are, if not in a rut, then at least on a plateau? Have we settled for the view that, after all our years on the plan, no further development is possible? That is not where Methodism began, nor where LPMA began! Keep on believing in the `impossible transformation'. 'Grace is that power which enables us to be what otherwise we could not be'.

And remember the heights to which John Wesley pointed: '... the heaven of heavens is love. There is nothing higher in religion.... When you ask others, have you received this or that blessing, if you mean anything but more love, you mean wrong; you are leading them out of the way.... You are to aim at nothing more, but more of that love described in the thirteenth of Corinthians. You can go no higher than this till you are carried into Abraham's bosom'.

The message and the messenger are inseparable. Hear what St Paul says: as God scours out of our life and preaching the selfishness and pride, as our life becomes cruciform, the resurrection life of Jesus begins to be revealed.' But notice where: 'Death at work in us (the preachers), life in you (who hear)'.

The test is very simple: do we make it easier for other people to believe that God loves them?

This weekend we are not just looking back with thanksgiving and celebration; we are also looking forward. The twentyfirst century stretches out before us. The world changes, bewilderingly, at an everfaster pace. And many churches in Western Europe often, though not always, find the mission field around us uncongenial and unresponsive. Is this Mission Impossible?

Jeremiah received his call to preach at what we might call five minutes to midnight in the history of Judah ­ the reign of Josiah, the last `springtime' before the cataclysm of the Babylonian conquest. For our situation, we cannot predict the future, nor should we try. But simply as human beings, we are bound to wonder whether things can go on as they are. We cannot help wondering what kind of world, what kind of church our children and grandchildren will inherit. But, as preachers, we can point to what P.T. Forsyth described as 'the things that really matter, and the power that really rules'.

Mission impossible? It always looks like that, and, if it doesn't, perhaps we have lowered our sights, or lost the vision. Always there is a hungry crowd to feed with the Bread of Life. And all we have are our five loaves and two fishes. But still the mission stands: 'Go into all the world'. And even there, at the end of Matthew's gospel, something of the old biblical template comes through: 'He's asking the impossible!' Objection, objection! 'Some doubted', says Matthew. But the promise stands, as well as the mission ­ even, it seems, for doubters: `I am with you always, even to the end of the age'.

Through the centuries of Christian history there has always been a pattern of continuity and change: the continuity of apostolic tradition, with the sharing of bread and wine, and the preaching of the Gospel at its centre, and also the change which comes from being led by the Spirit to respond to ever-new situations of mission. This weekend and tomorrow ­ with our thanks for all that is past, and our trust for all that's to come ­ represents just this pattern of continuity and change. The tasks of the future will be as daunting as ever: vocation, transformation, mission impossible. But, like a shining light leading us on, there stands, in continuity with the past, the promise of God: 'My grace is sufficient for you'.