Theophylact of Ohrid — as excerpted in the Catena Aurea on Luke 6:39-42

“Or else, If thou judgest another, and in the very same way sinnest thyself, art not thou like to the blind leading the blind? For how canst thou lead him to good when thou also thyself committest sin? For the disciple is not above his master. If therefore thou sinnest, who thinkest thyself a master and guide, where will he be who is taught and led by thee? For he will be the perfect disciple who is as his master.”