Here is a person who is going only halfway, hearing God's Word but doing nothing with it. How often do we hear a message, seeing it only as it applies to others, not to ourselves? Such a person may be able to hear the truth but filters it only through his clouded eyes, or worse, never sees how it relates to him at all.
We see these extremes in God's church today. Some people spend endless hours studying and conveying their discoveries to others, yet hypocritically do not follow their own advice or God's. They may even have understanding that could help others, but potential hearers see only the problems that drown out what they may be trying to say. As the saying goes, "Your actions speak so loudly that I can't hear a word you say." God wants well-rounded individuals in His Family, those who understand His way of life and cooperate with the rest of His family—not extremists who may be right in their knowledge but wrong in their overall viewpoint, including proper interaction with others.
Another extreme exists in those who are mere spectators, allowing others to preach at them without doing anything about it or even proving or disproving it for themselves. They take a "nothing ventured, nothing compromised" stance, which, though it may be technically correct, reveals a person who will not venture outside his "comfort zone." It is a stance guaranteed to produce no growth whatsoever, either in doctrine or in personal relationships. All this person sees is his own little world, a perspective that runs contrary to what God purposes for us. He is preparing us to be kings and priests in the world to come, both of which demand an outward, growth-oriented attitude.
Still another extreme behavior occurs in those who believe because they are told to, not because of their own involvement with God and His Word. They see what others tell them to see, not what they should see aided by God's Spirit. While it is good to be submissive, God wants us to seek Him (Deuteronomy 4:29; Isaiah 55:6; Amos 5:4; etc.) and prove all things (I Thessalonians 5:21; I John 4:1). A true Christian must be actively involved in pursuing God's way of life.
All these positions show an inability or lack of desire to see and respond to God's truth as we should. This is true physically. A myopic person cannot see things clearly enough to react properly. For instance, a nearsighted baseball player cannot see a pitch clearly enough to take an effective swing at the ball. A myopic Christian cannot see the truth clearly enough to use it in his life.