Jesus refers to cleaning the outside of cups and dishes while the inside remains corrupt. The image depends upon familiar concerns about vessels used for food and drink.
Jesus in Context
Cups, Dishes, and Ritual Cleanliness
Jesus uses the cleaning of eating and drinking vessels to criticize concern for outward purity without corresponding inward righteousness.
Introduction
Historical and Cultural Context
Purity practices in Jewish life could extend to vessels and eating practices. Cups, bowls, and dishes were ordinary household objects, but questions of cleanliness could carry religious as well as practical significance.
Why It Matters
Jesus deliberately turns the familiar distinction between clean and unclean surfaces into a moral image. Outward attention is inadequate when the inner condition remains corrupt.