Ezekiel 33:31-33

And they come unto thee as the people cometh, and they sit before thee as my people, and they hear thy words, but they will not do them: for with their mouth they shew much love, but their heart goeth after their covetousness. And, lo, thou art unto them as a very lovely song of one that hath a pleasant voice, and can play well on an instrument: for they hear thy words, but they do them not. And when this cometh to pass, (lo, it will come,) then shall they know that a prophet hath been among them.