Intercessory prayer sometimes gets a bad press. People say things like, ‘It’s telling God what he already knows’ or ‘There’s no point if God is in control.’ But we are in a spiritual battle as we engage in God’s mission to a hurting and sometimes hostile world. We can only advance by the power of God. And so we must pray. An incident in Mark 9 emphasises the point.
Some of Jesus’ disciples had been trying to drive an unclean spirit out of a boy. They failed miserably and it took Jesus’ arrival on the scene to sort the situation. Later the disciples asked, ‘why couldn’t we drive it out?’ Jesus replied, ‘This kind can only come out by prayer.’ (Mark 9:28-29)
Paul Barnett comments on this exchange between Jesus and his disciples. He declares:
The English translation here, and indeed elsewhere in this incident, masks the critical word ‘power’ as it occurs in the original. The disciples ask, ‘Why couldn’t we drive it out?’ or, more literally, ‘Why weren’t we powerful enough to drive it out?’ Jesus reply, ‘This kind can only come out by prayer’, or, more literally, ‘This kind is empowered to come out only by prayer,’ echoes their question and picks up the key word power.
This helpfully shifts the focus from prayer per se to the power of God released through prayer. It is not so much that faithful followers of Jesus believe in prayer, rather they believe in a prayer answering God who is all powerful and who loves to respond when we pray. Why did the disciples not pray before seeking to help the boy? Tim Keller says this:
The disciples are trying to exorcise a demon. But they have been trying to exorcise it without praying. How arrogant, how clueless they are about their inadequacy to deal with the evil and suffering of the world. The disciples tried prayerless exorcism for the same reason that they couldn’t understand why Jesus had to die – they didn’t see how weak and proud they were. They underestimated the power of evil in the world and in themselves.
As disciples we need a right estimate of ourselves, of the world, and of the mighty task that confronts us in mission. We are too weak to engage in any outreach without the power that comes through prayer. Do we realise this, or are we too conceited? We may object that such a word – conceited – is too strong, but effectively this is what we are if we believe we can engage in God’s mission without God’s enabling. Disciples on their own can do nothing in a broken world. This fact has not changed one iota since Jesus’ day. To be clear: we need his presence and power, by the Holy Spirit.
The words ‘only by prayer’ should be writ large over every mission venture, every challenge to the evils that hold people captive, every attempt to share faith with others, every desire to bring light to the dark places of the world. The powerlessness we frequently exhibit is so often linked to our prayerlessness. We simply must learn this foundational truth: ‘only by prayer’.
 Paul Barnett, Mark: The Servant King (Sydney: Aquilla, 2006 ), p. 170.
 Timothy Keller, King’s Cross: The Story of the World in the Life of Jesus (London: Hodder, 2013 ), p. 120.