Jesus finishes His question by giving the reason that should have been plain to them: food goes into the stomach, not into the heart. He asks them to reason from something everyone knows about the body. Barnes explains that food "Does not reach or affect the 'mind,' the 'soul,' and consequently cannot pollute it." Gill calls the heart "the seat and fountain of all moral pollution." The question clears the ground for what Jesus says next: the real source of defilement is inside a person, not on the plate.

Jesus answers it Himself: "That which cometh out of the man, that defileth the man" (Mark 7:20). He names the source: "For from within, out of the heart of men, proceed evil thoughts," followed by a long list of sins (Mark 7:21-22). He ends, "All these evil things come from within, and defile the man" (Mark 7:23). Matthew records the same question: whatever enters the mouth "goeth into the belly, and is cast out into the draught" (Matthew 15:17).

The Pharisees and "all the Jews" would not eat without washing their hands, and they also kept rules about "the washing of cups, and pots, brasen vessels, and of tables" (Mark 7:3-4). Barnes judges it probable that they washed "as a mere ceremony." "The draught" is the latrine; Gill notes it was called "the private house" by the Jews.

The last phrase, "purging all meats," is read two ways. Barnes says "The word 'purging,' here, means to purify, to cleanse": the body keeps what nourishes and casts out "the innutritious part of the food taken into the stomach." Gill agrees that "That which it leaves behind, is pure and nourishing." The Greek editions differ by one letter here: the Textus Receptus has katharizon, while editions such as Nestle 1904 and Westcott-Hort have katharizōn, and the ESV renders the phrase as Mark's own comment: "(Thus he declared all foods clean.)"

Jesus moved the whole question of clean and unclean from the outside of a person to the inside. The rules the Pharisees defended dealt with hands, cups and food. Jesus said none of those things can reach the heart, and the heart is where uncleanness starts (Mark 7:15, 21). Either way the last phrase of Mark 7:19 is read, the teaching of the passage is the same: food cannot defile a person before God.

This is good news and hard news at once. It is good news because no meal, no missed washing, and no outward accident can cut a person off from God. It is hard news because the problem is closer than we thought. If evil thoughts come "from within, out of the heart of men" (Mark 7:21), then outward washing can never be the cure. What people need is a clean heart, and outward washing cannot give that.