The twitter message "Lennox u rok my sox" scrolled on the screen as the smoke from the smoke machine rose from the stage.This is not your grandfather's Katoomba Christian Convention. Strange, because the men who walked on stage are both grandfathers, and proud of it.

'One' was in town for one night, and on Wednesday 31st of August, ten thousand people turned out to see Oxford Professor John Lennox and the author of 'Desiring God', John Piper, plead for Christians not to waste their lives.

KCC, known for the series of conventions every year at its Blue Mountains property, took a risk by booking out the Entertainment Centre. It shouldn't have worried as every seat was sold weeks in advance. Sydney Anglicans were among several denominations and interstate visitors who turned up in droves.

Even as the crowd was being warmed up, twitter messages with the hashtag #onesaviour were rolling on the big screens. Some pastors who had attended the two and a half day Oxygen conference with Piper and Lennox backed up for another night, bringing congregation members with them.

Garage Hymnal sang and the internet audience from other states and overseas was welcomed. The stress on twitter was not accidental, when John Piper asked the under 40's to raise their hands, it was clear a good two thirds were Gen X and younger.

One Life

The two speakers had differing styles, but one message.

John Lennox may not be the quitessential Oxford Don, his Northern Irish accent gives him away, but you could easily imagine the Professor lecturing his mathematics students.

He sprinkles his explanation of Matthew 17 with scientific language.

"In a nanosecond you will know that the kingdom of God is real. the question is can we be convinced of its reality before we die?"

"What is power as God counts power? The physicists don't even know what energy is...we can send people to to moon, we can't control our tempers, our lusts."

At one point, leaning across the lectern, it was like he was waking up students. "Listen to him!" he thundered, while stressing the need for deep Bible reading.

"We need to hear that voice. Are you listening to him, as his voice stirs in you the rustlings of eternity?"

Although sometimes it was hard to think that he's not a full time preacher, the talk was sprinkled with anecdotes from Lennox's real job as a mathematician. 

"I plead with you young people. Don't waste your brain. Use it to the full of your profession and use it to the full of the word of God. We need a generation of young men and women who are going to take this for real and decide to invest their lives in it. I'm so glad I was taught that when I was 18 or 19 and when I went to University I decided, with God's help, that I would do my mathematics to the best of my ability but I would apply the same energy at getting to know the word of God."

Use your time

Lennox said that would mean there would be less time for surfing, either on the beach or the net.

"How much time do you spend on the net, per day? How much time Twittering?" he challenged.

John Piper was a contrast in style, with sweeping hand gestures, explosive statements and "amazing" a favourite adjective. But these traits are well known on the net and from the Desiring God website. His message was as direct and to the point as the Irish brogue of Lennox.

He spoke of the 9/11, the Tsunami and even the local disaster of the tragic Brisbane house fire in which 11 died.

From Luke 13 and the Tower of Siloam, Piper summed up the response of Jesus.

"It shouldn't astonish that there were calamities that took out this many people. What should astonish you is that you are still here breathing."

Borrowing from the style of his 18th century hero, Jonathan Edwards, Piper said "My life hangs by a slender thread of divine kindness. We deserve hell. We are sinners. Every minute in this room is a gift and the message is listen up and resolve not to waste your life."

If pastors left the Oxygen conference refreshed, 10 thousand congregation members left the entertainment centre challenged, chastened and determined not to waste their lives.

The twittering became less about 'longest bathroom queue ever' and 'so many people at #onesaviour is killing my internet connection.' The last tweet I saw said 'John Lennox told me to tweet less.'