And he told them a parable, "Can a blind person guide a blind person? Will not both fall into a pit? No disciple is superior to the teacher; but when fully trained, every disciple will be like his teacher. Why do you notice the splinter in your brother's eye, but do not perceive the wooden beam in your own? How can you say to your brother, 'Brother, let me remove that splinter in your eye,' when you do not even notice the wooden beam in your own eye? You hypocrite! Remove the wooden beam from your eye first; then you will see clearly to remove the splinter in your brother's eye. (Lk 6:39-42)
Jesus is giving a warning to his listeners that they should be careful about choosing their guides. The guides should be aware of their paths and pitfalls. If not they themselves fall a prey to their guidelines or they will make their followers to fall into it. Guides should be aware of their paths and their own vision should be clear.
The next comparison is between a teacher and a student. Comparisons are not good in themselves but here Jesus is making use of it to communicate a particular message. The message is that the students will one day be teachers and not more than that. He can never become a superior to his teacher.
The next teaching in this passage seems to be a verbal cartoon (wooden beam in the eye). It only says that you cannot criticize another. What one criticizes the other is often the mistake he does himself. It is a sort of projection.
