William Burkitt on Luke 6:39

Our Saviour doubtless applied these words to the scribes and Pharisees, the Jewish leaders, doctors, and teachers, who being ignorant of the spiritual sense of the law, (interpreting it only to the restraining of the outward man,) were very unfit to instruct and lead others; for where one blind man leads another, both are in danger of the ditch; that is to run into ruin and destruction.

Learn, 1. That ignorant, erroneous, or unfaithful ministers, are the greatest plague, and sorest punishment, that can befall a people.

2. That Christ having forewarned us of such guides, to follow them will be an inexcusable sin and folly, and never free us from the danger of destruction, but rather be an aggravation of our condemnation: If the blind follow the blind, both will, inevitably yet inexcusably, fall into the ditch.