Former investment banker and Chairman of Alpha International Ken Costa gave a rousing talk at HTB Church in London on Sunday, in which he discussed the characteristics of a growing church.
Following on from Nicky Gumbel's talk on friendship at last week's Leadership Conference, Costa looked at the early church in Acts chapter 2, noting that it is our first example of "what happens when the Spirit of God actually comes upon a people".
The thrust of his impassioned sermon centred on the church as a group of friends who are "radical and real".
"This simple story [in Acts] is raw and it's compelling, it's radical and it's real," he declared.
"Radical means going back to the root," he explained, noting that the early church met in one another's homes, simply breaking bread together and enjoying each other's company.
"They devoted themselves to the fellowship: they were generous with their friendship...generous with their money, time and relationships," he continued.
Costa was keen to note that meeting in homes, as opposed to traditional places of worship such as the synagogue or temple, would have been hugely controversial at the time as women and children were not allowed in these 'holy' places, but would have of course been in the home.
What's more, the Bible tells us the members of the early church "devoted themselves to the apostles' teachings"; unheard of given that Peter wasn't a rabbi – he wasn't even trained or a scholar. The early church was radical in its structure, and in its way of building community.
The five marks of a gathering of friends are this, Costa continued: friends share with one another; they show each other love; they shoulder one another's burdens; they sharpen each other's lives; and they have something to shout about – they show passion.
"Authentic trumps relevant every time," he said. "The distinguishing feature of our faith is the same as that group of people. An encounter with Jesus Christ changes everything; it doesn't just give you a new religion - it changes the way you think; the way you deal with your relationships; where you work; how you work; the attitude of your hear; the way you use your money; the way you give; your generosity of spirit...it gives unimaginable joy of the love of Jesus and unbreakable friendships."
Life lived for Christ is radical: "He revitalises our lives, redirects them, and resets the whole way we do life."
Costa then spoke of the joy that comes out of fellowship with fellow believers. He referred to verse 46 of Acts chapter 2, which says, "They broke bread together in their homes and ate together with glad and sincere hearts."
"At the birth of the church, when the spirit of God has come upon them, they are glad, they are joyful...because they are birthing a new network," he noted.
Addressing the congregation, Costa then concluded, "We are part of an unbroken network; a network that spans the world; unbroken until Jesus returns, that can meet together and pray together and see things changed, that sees signs and wonders in our midst that the people around us will look in awe at what the people of God are doing.
"It's an amazing, exciting, passionate activity isn't it? Hallelujah!"