I was listening to Plato’s Phaedrus this morning in the car, and was struck by a passage in which he uses an illustration very similar to one that Jesus uses:
If it were true that we ought to give the biggest favour to those who need it most, then we should all be helping out the very poorest people, not the best ones, because people we’ve saved from the worst troubles will give us the most thanks. For instance, the right people to invite to a dinner party would be beggars and people who need to sate their hunger, because they’re the ones who’ll be fond of us, follow us, knock on our doors, take the most pleasure with the deepest gratitude, and pray for our success. (Phaedrus 233d-e, Cooper’s edition)
The point Plato is developing is not the same as the point Jesus makes, but it makes me wonder whether this sort of hypothetical situation was proverbial.