“Once again Jesus addresses the people: ‘ I AM the Light of the world. No follower of Mine shall wander in the dark; he shall have the Light of Life.”
Notice John emphasizes that Jesus speaks “once again”. Jesus continually tells the people the same truths: the world is wrapped in darkness, and He is the only light source.
As a matter of fact, when a person who is blindfolded or in a dense fog is directed to walk in a straight line from point A to point B, the person will start out relatively straight but gradually begin to turn until he is walking in complete circles, eventually winding up where he began, at point A. All the while, the person will strongly believe he is walking in a straight line. Only after the blindfold is removed will he realize that he had no sense of direction and was literally wandering in the dark, wandering in circles — going absolutely nowhere.
Take off the blindfold, remove the dense fog and the person is able to walk in a relatively straight line. Now the same amount of effort is put forth by the person whether he is blindfolded or able to see. In both conditions, the person is moving forward. The difference in the outcomes is the difference between the conditions of darkness and Light.
So, when we are “followers” of Jesus Christ, we walk in a straight line not due to our forward motion or our own efforts, but because we have the Light source needed to arrive at our destination.