Six in the fourth place means:

Nothing that would not further modesty
In movement.

Everything has its proper measure. Even modesty in behavior can be carried too far. Here, however, it is appropriate, because the place between a worthy helper below and a kindly ruler above carries great responsibility. The confidence of the man in superior place must not be abused nor the merits of the man in inferior placed concealed. There are officials who indeed do not strive for prominence; they hide behind the letter of ordinances, decline all responsibility, accept pay without giving its equivalent in work, and bear empty titles. This is the opposite of what is meant here by modesty. In such a position, modesty is shown by interest in one's work.