Albert Barnes Commentary Matthew 15:11

"Not that which entereth into the mouth defileth the man; but that which proceedeth out of the mouth, this defileth the man." — Matthew 15:11 (ASV)

Not that which goeth into the mouth, The disciples were charged with being sinners for transgressing the tradition of the elders, in eating with unwashed hands. Christ replies, that what they should eat could not render them sinners. The man, the moral agent, the soul, could not be polluted by anything that was eaten. What proceeds from the man himself, from his heart, would defile him.

Defiles. To pollute, corrupt, to render sinful.

See Barnes on Matthew 15:10.