In what they lay on their learners they are not sincere, nor do they put forth all their ability in teaching them. What they inculcate is contrary to what is right, and the learners are disappointed in what they seek for. They may seem to finish their work, but they quickly give up its lessons. It was from these four things that the teaching was so effectual and flourishing. Prohibition of evil after it has been manifested meets with opposition, and is not successful.
Instruction given after the time for it is past is done with toil, and carried out with difficulty.
The communication of lessons in an undiscriminating manner and without suitability produces injury and disorder, and fails in its object. Learning alone and without friends makes one feel solitary and uncultivated, with but little information. Friendships of festivity lead to opposition to one's master. Friendships with the dissolute lead to the neglect of one's learning. These six things all tend to make teaching vain.