Mike Pilavachi is between Soul Survivor weeks. The youth-oriented holiday conferences – due to come to a natural conclusion next year – have had a huge impact on British Christianity over the 25 years they've been running, and this year is no exception. After two weeks, one in Kinross and one in Stafford, he says: 'So far it's been wonderful. Over 480 young people have given their lives to Jesus and we've had great feedback – there's been a real sense of community, a real sense of family.'

Any highlights so far? He has two.

'There was one night at Week A (Stafford) when the Holy Spirit began to move in a wonderful way – I couldn't preach, I saw young people filled with the Holy Spirit and I saw the looks on their faces.'

And second: 'One evening at Week A, a guy came up at the end of the meeting with his 13-year-old-son and said, 'I want you to know, my son came forward tonight to give his life to Jesus. Twenty-three years ago, when I was a teenager, I came forward as a teenager to give my life to Jesus. That's what Soul Survivor means to my family.'

That's coming to an end – but as Mike says, 'I'm fine with that. Jesus is my life, not Soul Survivor. We believe we were obedient to start it, and we believe we're obedient to finish it.'

The stories say something about Mike, and about the ministry he's part of with Andy Croft at Soul Survivor Church, Watford. He's an intensely emotional man, who feels things deeply. And for him, it's all about Jesus.

The pair have written a new book together, Lifelines: Sound advice from the heroes of the faith. It's framed around the stories of biblical characters such as Elijah, David, Ruth and Daniel, and is rooted in serious Bible study. Each chapter ends with discussion questions for group work. But what's notable about it is the way it also draws on the authors' personal experience and on their immersion in the real-life stories of God's people today. The Bible characters walk alongside us in the here and now.

Some of the experiences Mike and Andy recount about themselves are quite raw; others are, let's say, unflattering. But that's deliberate.

'What we've discovered in the last few years is that the more we're honest, transparent and vulnerable, the more it creates a sense of family,' Mike says.

'Who wants to pretend? Looking at these characters, the Bible represents them as very fallible but God uses them.'

He instances an event a couple of years ago, when Andy had been experiencing anxiety attacks and preached a sermon about it. 'It was from the point of view, "I'm not there yet." What that did for the church was amazing. It gave everyone permission to be open about their struggles.

'One of the things he said was that he'd always equated love with success – if he succeeded he'd be loved, if he failed he wouldn't be. He said to the church, "To be really honest, before I got up to speak this morning I couldn't help thinking, "I need to do this well or they won't love me."

'When someone shares their humanity, everyone loves them. As a result, our church is incredibly loving , kind and merciful. Intentionally so.'

They wrote the book together, varying who took the lead on different chapters and always talking through the different passages. The depth of their relationship comes through on every page, with honest – though only semi-serious – acknowledgments of their different strengths and weaknesses ('Andy does the theology, I do the jokes,' Mike says.)

When I point out that it's quite unusual to see such a healthy and realistic ministerial partnership in a large and conventionally 'successful' church, it sparks a mini-sermon. 'This is totally not a one-man ministry or even a two-man ministry,' he says. No one, he stresses, is on a pedestal. 'At the festivals in the summer I'm surrounded by people who come up and ask me to write in their Bibles. When I go back to church, someone will ask me, "Have you put on weight?"'

His model of church is that it's a family, not a business. 'In a business, you hire and fire; in a family, you raise up sons and daughters.

'I was at a conference where one of the speakers said you have to "buy the best to be on your staff"' he says, horrified. 'But someone's got to raise the best for you to buy them.

'Around teachers people learn things, around fathers people grow and gain confidence. That means loving one another and being committed as a family.'

That conference might have been the one they write about in their book, of which they say: 'The agenda was to create prominent, powerful churches that could have significant influence. Needless to say we were rather pleased with ourselves for even getting an invitation.'

As the event progressed, they describe sinking lower and lower into their seats as a presenter described the ideal Christian leader as someone 'you might get if you crossed Mother Teresa and Steve Jobs with Nelson Mandela and Wonder Woman': 'By the time we left we knew we had been invited by mistake. Jesus has changed us and yet we're still a work in progress.'

Mike is viscerally opposed to that kind of super-efficient, streamlined, performance-driven enterprise. '"If you carry on with these gimmicks or this branding, if you do this you can change your life, you too can be like us if follow these five rules" – Oh, please.' (Another of their stories in the book is of how the church's sung worship became too professional – so they stopped doing it until it became genuine again.) 'The early church was devoted to the apostles' teaching, to prayer and to one another. They met together daily. Family – that's what the world is crying out to see.'

And, he says: 'If there's a reason things have worked for us at festivals and at church, it's not because we're slick. We waddle on to stage and get confused about the notices. There are much better preachers than us, but people look at us they feel safe and secure.

'The main questions people are asking are not, what's their doctrine on the resurrection, or what about sexual ethics – though I'm absolutely clear about those things – it's 'Can I belong? Will they accept me here? Do they rejoice with those who rejoice and mourn with those who mourn?'

And it's as they track the messy inadequacies and frequent failures of their Bible characters that their book connects with the stories of today and leads back to Jesus.

'Never forget, they conclude, 'the God of John, Elijah, Ruth, Joseph, David, Daniel, Samson and Mary is your God... You need not be afraid; he will never leave you, he will never forsake you. With your trust placed in him who is beside, behind and before you, you can be at peace: your life too, will point to him.'

'LIfelines' by Andy Croft and Mike Pilavachi is published by David C Cook, price £.9.99.