Father Brown makes a point about some of the Bible's rules being inapplicable. Specifically he references not weaving two different fabrics together. In the Bible Leviticus 19:19 and Deuteronomy 22:11 God says not to mix linen and wool together. Interestingly, scientists have now proven linen and wool woven together increases passing off body electricity, and in extreme heat can cause fever and blisters.