There was a Scottish tradesman, a painter called Jock of course, who was very interested in making money where he could. So he would often thin down his paint to make it go a wee bit further - as it happened, he got away with it. Eventually, the Church of Scotland decided to do a big restoration on the roof of one of their biggest Churches. Jock put in a tender and because of his price was so competitive, he got the job. And so he set about erecting the trestles, and putting up planks, and buying the paint. Yes I'm sorry to say, thinning it down with Turpentine.
Well, Jock was up on the scaffolding, painting away, the job nearly done,when suddenly, there was a horrendous clap of thunder, and the sky opened and the rain poured down, washing the thin paint from all over the Church and knocking Jock off his scaffold to land on the lawn among amongst the gravestones, surrounded by telltale puddles of the thin and useless paint. Jock was no fool, he knew this was a judgement from the Almighty, so he fell on his knees and cried, " Oh God! forgive me! what should I do?"
And from the thunder, a mighty voice spoke. "Repaint, and thin no more!"