If your group is all rock solid Christians, skip this. Otherwise, this really gets their attention.
Hold up a twenty in your hand in front of the group. US readers could probably get away with a ten. Simply say “Who would like this?” Then, just wait for someone to come and take it out of your hand. This will take about 30 seconds. The rest of the group will be VERY dismayed that that was all they had to do.
Discuss with the group why they didn’t come to take the money. Reasons are: I thought there was a catch, I didn’t think you meant it, I thought I would have to do something dumb, etc. Then explain that the twenty is God’s love and help them to see how those same excuses often keep up from just going up and claiming God’s love. The kids talked about this for weeks – mostly to see if I was handing out more twenties!