Pesachim 18 Always go to the Source

The Torah will at times provide a source for a law that we can just as easily extrapolate using the method of Kal VaChomer - learning the more obvious from the less obvious. (In our case the law of diminished contagion regarding food and liquid.) This principle (as well as the law of contagion itself) introduces the idea that something or someone that has been inspired by the original source of wisdom is qualitatively different from one who has only had access to a replica of the original. Or...