Some pointers on preaching the passion narrative, mainly for my own benefit as I prepare for Friday...
1. Tell the story. Ideally read a decent chunk of the Biblical narrative, but then in the sermon make sure that what comes across is that something happened. We can hardly dwell too long on the fact that the crucifixion of Jesus Christ was a real thing that took place in real space and time. All the theological and soteriological significance of this event depends on the fact that it was an event.
2. Don't forget the resurrection. None of the really important things about the cross can be seen except from the viewpoint of the resurrection. Okay, that is an overstatement - some people did see (thief on the cross, centurion by the cross), and other people ought to have seen (because of the Old Testament - cf. Road to Emmaus) - but in general it is a mistake to preach the cross as if we didn't know the rest of the story. The resurrection reveals that the one hanging on the cross is the King, reigning even in his death; the resurrection reveals that this sacrifice is acceptable to God; the resurrection reveals that God has vindicated himself in his justice and grace at the cross. Even the identity of the sufferer is not truly revealed without the resurrection. So, preach Friday with one eye on Sunday; or perhaps better, preach Friday as if it were already Sunday morning.
3. Avoid painting Jesus as a victim. The Jesus of the gospels is a sufferer, and indeed an innocent sufferer. But he isn't a victim. Reading the gospel narratives, at what point is Jesus not in control? Even when bound and flogged, isn't he the King? Doesn't the ironic crown of thorns actually mock the mockers? There are all sorts of reasons, some of them apparently good, to present Jesus as a victim; there are lots of victims in the world, and we want to bring home that God is with them in their suffering. But there is no way we can make the gospel narratives portray a victim. He is a co-sufferer, but he is this as the Lord.
4. Don't give the impression that God was at the end of his resources. The cross of Christ was not a fall-back position, or a last ditch attempt to redeem a terrible situation. God didn't give himself away at the cross; he didn't empty the tank to save us. The cross was always the plan. If there are aspects of the gospel story which do seem to point in this direction (e.g. the parable of the tenants, with its sequence of servants ending finally in the sending of the son), read in the context of the whole gospel we have to say that the giving of the Son represents not an exhaustion of God's grace - not the final last effort of God - but the fullness and wealth of God's grace. It as at the point of his death, when he gives himself for us, that God shows the inexhaustible riches of his love for fallen humanity. He's rich, not broke.
5. Don't put the ball in our court. We can easily give the impression that the cross of Christ only has significance if we respond to it - as if God in Christ has done everything that he can, and now it's up to us to react appropriately. Of course we should preach with an appeal; of course we want people to respond to the cross of Christ. But the point is that when we preach Christ crucified we preach the sovereign Lord. In him, sinful humanity is put to death; in him, God's judgement is taken from us, falling instead on the willing Judge. This is true in him. Our appeal is not: please complete in your own heart Christ's unfinished work! Our appeal is: accept the truth about yourself as it is in Christ Jesus! The cross of Christ does make an appeal, but it does so in the form of a claim: you are no longer free to wander on your own way; Christ's death is for you, in your place, and therefore it is death pronounced on your sinful existence.