Regeneration: posh word for 'new birth' - as in what Jesus said:"No-one can see the kingdom of God unless he is born again." (John 3:3) You can't see it happening, and it's entirely God's work.
Conversion: the human act of turning from sin to trusting in Jesus for forgiveness and new life - as in Mark 1:15: "Repent and believe the good news!"
These two things obviously go hand in hand. But as Graham Daniels pointed out last week when I was away with St Andrew the Great, Cambridge, knowing the difference affects how we tell people about Jesus.
We can bring about 'new birth' no more than we brought about our own natural conception. (Something we probably don't want to think about too much.) So here's the danger: it's possible for someone to say 'Yes' to the message about Jesus: 'Yes, I'll become a Christian!' Someone might do that for all sorts of reasons - the heat of the moment; an emotional response to a great preacher, etc. But it's possible to do that whilst not actually being regenerated.
How would you know if someone's 'conversion' was true or false? In the words of Bob Marley - time will tell. The bigger deal than praying a prayer of response is: are you still trusting Jesus in a year's time, or 10 years' time? That would be the proof that you're truly regenerated.
Put the other way round, there can be a big time delay between regeneration and conversion. The 'seed' might be sown when someone heard the gospel in their teens, but never make a proper response until 20 years later. You might be regenerated as a small child, but only express a response later on.
Therefore, the thing to avoid is always pressing for a response here and now in people. That's not the big deal - though it might stroke our egos for people to visibly respond to our message. In fact, that sort of thing could do real harm if people are not truly regenerated - which is God's work alone. We wouldn't want people thinking they're Christians when they're not, would we?
No - our work is to sow the seed of the Word - tell people about Jesus. And pray. Our job is simply to be like the midwife, facilitating, helping the process along. Not manipulating people towards a response. That's why our work as a church must be steady, low-key, watching for where people are responding, patiently encouraging people to respond - knowing when to 'push', and when to step back!