Jesus recognized that having two ears attached to our heads does not necessarily make us listeners.  Often our attitudes serve to filter out God's voice.  For example, you won't have ears to hear God if you desire to continue running your own life.  If you ask God to give you His opinion about something, but you reserve the right to ignore that advice if you don't like it, you won't be in much of a position to hear.  You also won't have ears to hear God if you only listen for Him when you are in trouble or are facing a tough decision.  Aren't you frustrated by a "friend" who only calls when they need you to bail them out of trouble?  You will be much more likely to hear God's voice in the crisis times when you are in the habit of listening to Him day by day.