The Enarrations, or Expositions, on the Psalms

⁴ But let us return to what was just now read from the Gospel, relating to the verse before us, “Our mouth was filled with joy, and our tongue with delight:” for we are inquiring what mouth and what tongue. Listen, beloved brethren. The Lord was scoffed at, because His disciples ate with unwashed hands. The Lord answered them as was fitting, and said unto the crowds whom He had called unto Him, “Hear ye all, and understand: not that which goes into the mouth defiles a man; but that which comes out of the mouth, this defiles a man.” What is this? When He said, what goes into the mouth, He meant only the mouth of the body. For meat goes in, and meats defile not a man; because, “All things are clean to the clean;” and, “every creature of God is good, and none to be refused, if it be received with thanksgiving.”...