Personal opinion:

The author believes that only those who have no distractions can learn the sage books. Otherwise, those who have selfish distractions will use those behaviors to satisfy their selfish desires when they see some good deeds. When you hear a good word, you will use it to cover up your shortcomings. It's like giving soldiers to the enemy and food to thieves.

Personally, I think people who choose to read sage books are not bad. After all, there are too many selfish distractions to read the words of saints. For example, in order to get rich, a person harms the interests of others for the sake of profit, and even steals and abducts. Even if you know that "a gentleman loves money and takes it wisely", he will be mercenary and insatiable.

However, if this person is thoughtful and shrewd, it is easy to confuse all beings with external performance and behavior, just like a wolf in sheep's clothing, which harms people invisibly.