Mark 7:4
When they come from the marketplace they do not eat unless they wash. And they observe many other traditions, such as the washing of cups, pitchers and kettles — the marketplace contact with Gentiles or non-observant Jews could create ritual impurity; the washing upon return is the decontamination ritual. The many other traditions suggest that the handwashing controversy is the representative case of a broader system of purity regulation that the Pharisees applied to everyday domestic life.