Six at the beginning means:

Hold to him in truth and loyalty;
This is without blame.
Truth, like a full earthen bowl.
Thus in the end
Good fortune comes from without.

Fundamental sincerity is the only proper basis for forming relationships. This attitude, symbolized by a full earthen bowl, in which the content is everything and the empty form nothing, shows itself not in clever words but through the strength of what lies within the speaker. This strength is so great that it has power to attract good fortune to itself from without.