Why the ancient times can "draw the ground for the prison, cut the wood for the officials"

The first idiom, this is the need for two reasons, first of all, the individual moral character is high, made a mistake, their own constraints on their own more; Secondly, the moral climate of the whole society are the same, people are trusting each other. Although it is the ideal state of the ancient Chinese scholars, it does reflect the integrity and goodness of the ancients.

The second idiom, the original meaning is not to be insulted by the jailer, even if the jailer is made of wood can not see him. It describes the fierceness and fearfulness of the jailer. The meaning with the first sentence is different, and not carve a wooden jailer to watch on the line. This sentence is the ancient scholars, moral and noble people, do not want to see the appearance of the brutal jailer, can be extended to the reluctance to enter the prison, but to strengthen the restraint of their own behavior.