Theophylact of Ohrid — as excerpted in the Catena Aurea on Mark 7:1-13

“For the disciples of the Lord, who were taught only the practice of virtue, used to eat in a simple way, without washing their hands; but the Pharisees, wishing to find an occasion of blame against them, took it up; they did not indeed blame them as transgressors of the law, but for transgressing the traditions of the elders. Wherefore it goes on: For the Pharisees and all the Jews, except they wash their hands oft, eat not, holding the tradition of the elders.”