Mark 7:20

And he said, that which proceedeth out of the man, that defileth the man.

This truth appeared dramatic enough on the occasion when Jesus uttered it, but it was not a new thing at all, having been emphatically taught in the Old Testament. The "heart" is mentioned no less than 74 times in the Book of Proverbs alone where it is set forth as the fountain source of all that comes out of life. "Keep thy heart with all diligence; for out of it are the issues of life" (Proverbs 4:23). The Pharisaical shift of emphasis from the heart to externalism resulted from their evil nature and not from God's sacred law. In such a perversion, they were not innocent but guilty.