The last sentence is cautious in knowing and doing, and the next sentence is how to treat it lightly. The whole sentence is: "disaster prevention first, then no disaster prevention." Knowing and being cautious, it is natural for a gentleman not to stand under a dangerous wall. "

Take precautions to avoid hurting feelings afterwards. Smart people know this, so they will act cautiously. A gentleman will not stand under a dangerous wall to avoid unnecessary trouble.

Source: Appreciation of Mencius Dedicated: This sentence contains two aspects. The first layer means nip in the bud and don't go to dangerous places; The second meaning is to leave immediately when you find yourself in danger.

Revelation: A true gentleman should not only bravely stand under the dangerous wall, but also turn the tide and help the building collapse.