This is the text of a sermon that I preached  in the chapel of Jesus College, Oxford back in 1996.  (My book Elementary Geometry had just been published and gets a shout-out at the beginning, but is not important to the argument.) The Old Testament scripture was Jeremiah 31:31-34 and the New Testament scripture was Romans 8:1-17.  Along the way it tells you a little about how I think of faith, life, mathematics, and the connections between them.

ONLY THOSE WHO KNOW GEOMETRY ARE ALLOWED IN HERE

Don’t worry, it is not an invitation for half the congregation to leave, nor is it yet another sales pitch by Dr Roe on behalf of his book. These are the words which, according to legend, were inscribed over the gateway of the Academy in Athens, the prototype of the Western university. Like some politicians today, the founders of the Academy were interested in the power of the educational system as a means of moral improvement; and they believed that this improvement would come about as their students focused their attention less on the world of sight and touch, decaying and imperfect as it was; and more on the world of changeless and enduring Forms. Hence the importance of mathematics. `The objects of geometric knowledge are eternal’, wrote Plato; `geometry compels us to contemplate true reality rather than the realm of change’.

The basic contrast set up here, between the `lower’ material world and a `higher’ spiritual realm, invisible to us, but accessible through rigorous training and mental discipline, is one which has passed into Western thought in general and has become part of our mental furniture too. So much so that when we read in Romans of the dramatic contrast between `flesh’ and `spirit’ we are likely automatically to assume that this is another version of the same thing. Surely, we think, when Paul speaks of the `flesh’ he means our `lower nature’ – especially perhaps our sexual nature, since the modern understanding is that Paul, in common with more or less everybody born before 1960, had terrible hang-ups in this department – and we think that when he speaks of the `spirit’ he means the `higher’, religious part of ourselves which checks the unruly lower nature and brings it under control. That is what we think. But we are wrong. Paul is not offering a programme to replace passion by piety. His vision is a good deal more radical, and more exciting, than that.

What is Paul getting at, then, when he talks of the Spirit? Let me encourage you to open up the text and take a look at v.16. Here we find that Paul knows of something he calls `our spirit’ – our interior life, perhaps almost in the Greek sense. But what he is preoccupied with in this passage is not the capabilities or otherwise of `our spirit’, but the presence, in the lives of those he addresses, of a different power – the Spirit of God himself. As a provisional definition, for us to test against the passage, let us say that by the Spirit Paul means the presence of God, in the experience of believers, through the death of Christ. I would like to unpack each of these phrases by reference to the text; and along the way, perhaps we will find out a bit about what Paul means by `flesh’ as well.

1. The Spirit means the presence of God. How do you think of the God of the Old Testament? Some see him as a remote and alarming figure, emerging from thick darkness only to issue terrifying commands. But the Old Testament itself, which does indeed contain awesome depictions of its Lord, also thrills with desire for him. `My soul longs for the dwelling-place of God’ writes the author of Psalm 84, and s/he speaks for many OT writers who go beyond the Law of God to longing for the personal presence of God Himself. This is why there’s so much focus in the OT on the temple as `the place where God makes his home among his people’. And in our OT reading Jeremiah ventures an even bolder hope; that God’s dwelling-place will be, not in a building, but in the hearts of his servants. In Jeremiah’s vision of the future, knowledge of God is no longer a matter of theory, which must be taught and learned; it is a matter of friendship, even of family. Paul sees this hope fulfilled in the coming of the Spirit. `You are God’s temple’, he writes in another place, picking up the Old Testament language; `and God’s Spirit dwells in you.’
2. The Spirit is present in the experience of believers. Look back to verse 15: `When we cry out, Abba, Father, it is the Spirit of God bearing witness with our spirit that we are children of God.’ Paul does not know the Roman Christians personally; he is writing, as it were, to introduce himself, because he hopes to visit them later. Nevertheless he is confident that they, like he, are familiar with this particular experience, of crying out under the power of the Spirit as he brings home to them the reality that they personally are children of God. I don’t think we need spend too much time theorizing about what exactly this `crying out’ is – whatever it is, it is something that we would probably call an `ecstatic’ experience, and from his other letters, it seems to be the case that Paul expected that all churches would be marked by Spirit experience of this type. But notice again the `together with our spirit’ in this verse. We’re not talking here about an experience simply of abolition, a `Spirit takeover’; but an experience in which the believer participates with freedom and appropriateness. Here’s an example. If I tried to sing in the chapel choir it would be a disaster. My contribution would be a series of bum notes which neither followed the score nor uplifted the heart. But whenever I come to worship I am putting myself forward to join with choirs of angels making music of inconceivable beauty. How dare I? Only, says Paul, because the Spirit of God will aid the voice of my spirit; we shall sing together.
3. The Spirit is experienced through the death of Christ `If the Spirit of him who raised Jesus from the dead dwells in you’, writes Paul in verse 11, `then he will give life to your mortal bodies also.’ The presence of this Spirit is not something for which we are qualified; Paul isn’t a self-help guru giving us some new insight which will `unlock our potential’. In fact, Paul says, there are good reasons for thinking life in the Spirit to be impossible; but very recently, within Paul’s own lifetime in fact, God has done something which has reversed all expectations and has made the impossibility into a possibility. This `something’ is the coming of Jesus Christ. He it was who brought the real presence of God in human form: `something greater than the Temple is here’. He it was too who brought to some the experience of speech that was clear and free and appropriate; and to others sight, or full stomachs, or the forgiveness of sins. In other words, Jesus did on earth the things that Paul says the Spirit does now. Yet there isn’t a direct line from Jesus’ earthly ministry to the poured-out Spirit; between them stands the cross, the sign of contradiction. And it is in looking here that we will finally get a picture of what Paul means by the `flesh’.

When God draws near to someone, there’s a struggle in that person’s heart between love and fear. Yes, I want to follow him; but what will he do, if I submit to him, what will it cost me? You can trace this conflict through all the characters in Jesus’ story, and you will find that, in the end, and in various ways, they all chose fear rather than love. The common people; the religious people; the disciples; the political authorities – the verdict is the same. They could not submit – the phrase is from verse 7. They could not put themselves under the authority of God present among them. Paul uses the term `flesh’ to signify that this is the same for everybody. There is that in us which cannot submit to God either. Our sins can’t satisfy its appetite, our religious practices can’t keep it under control, and even our carefully nuanced ironies can’t obfuscate it. Only the fire of God’s judgment can destroy it. But, Paul says, that fire has already fallen. `By sending his own Son, in the likeness of sinful flesh, God condemned sin in the flesh’. Believers, identified with Christ in his death, have experienced the fire of the judgment of God; yet amazingly they are not destroyed, but set free to live a different kind of life, one whose central desires come from the Spirit – `God condemned sin in the flesh, in order that the just requirement of the law may be fulfilled in us, who walk not according to the flesh, but according to the Spirit.’