Preaching on any subject

It was preaching each Sunday that made Father Brown a few pounds extra on the side. You see he had a weekly bet with the altar boy that he could improvise a sermon on any subject at a moment's notice.

Each week the altar boy left a note on the lectern, and each week the priest ad-libbed his way through. Finally the youngster thought he had the priest stone cold by leaving a note that merely said: 'Constipation'.

Totally unconcerned, Father Brown glanced at the paper looked up and began:

'And Moses, taking the tablets, went up into the mountain ...'