Leslie M. Grant · Comments on the Gospel of Matthew

Peter however thinks of verse 11 as a parable, and asks for an explanation. This is painful ignorance, as the Lord tells him, but he is not alone, for there are many Christians who consider only externals, and forget that the real index of what is defiling is that which one allows to proceed out of his mouth. For these come from the heart., which is the source of evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies. It may not be that every one of these is always expressed from the mouth before the act takes place; but every one proceeds from the heart, which commonly expresses itself in the words of the mouth. If the mouth expresses hatred, this is the principle of murder (1Jn.3:15). One who is adulterous will usually betray it by corrupt language. A thief will likely express himself covetously. Wisely indeed does Proverbs 4:23 tell us, "Keep thy heart more then anything that is guarded, for out of it are the issues of life" (J.N.D.trans). The Lord then closes the subject with the declaration that to eat with unwashed hands does not defile a man.