The way I figure it, if you believe and propagate an "old adage", it becomes yours. You can find a biblical parallel for much of the wisdom that is passed down by sayings in our culture, but that doesn't mean that anyone who discovers that wisdom got it from the bible....or that the writers of the bible were the first to discover the wisdom that they wrote.....wisdom gets rediscovered many times, and explained in many ways.....just as musical themes tend to repeat....