Painting this church

Bill was short of money and was out looking for a job. Pastor Nelson offered Bill $500 to buy paint and paint the church. Well Bill went out bough some paint and started painting the church. He discovered that he was using more paint than he expected so the added some thinner to the paint, well it is still covered but not as well as it did at first. Well he still was using more paint than he wanted to use so he added still more thinner to the paint. Well the paint was too thin cover well but Bill still kept on painting. All of a sudden there was a bolt of lighting and a loud voice from the sky proclaimed, Repaint and thin no more.