Back in primitive days, there was a very gentle tribe which, unfortunately, encountered some cannibals. The cannibals chased them and ripped off parts of their bodies, even their thighs and shins. Those who managed to escape finally came upon another peaceable tribe whose chief invited them to relax and enjoy themselves until they were healed.
He welcomed them proudly to a "first" in the world's cultural history; the presentation of a play. Alas, since it was the first play in the world, the acting was pretty bad. The embarrassed chief told the wounded visitors that they could throw rocks if they wished.
As he strode away in disgust, he muttered, "He that is without shins among you, let him stone the first cast!"