Modesty expresses itself in one’s outward behavior without the need to call attention to oneself. If you relate with the world in modesty there will be no resistance to your intentions. You good reputation will grow and you will be successful.
Read the text from Richard Wilhelm's translation of the I Ching
It is the law of heaven to make fullness empty and to make full what is modest; when the sun is at its zenith, it must, according to the law of heaven, turn toward its setting, and at its nadir it rises toward a new dawn. In obedience to the same law, the moon when it is full begins to wane, and when empty of light it waxes again. This heavenly law works itself out in the fates of men also. It is the law of earth to alter the full and to contribute to the modest. High mountains are worn down by the waters, and the valleys are filled up. It is the law of fate to undermine what is full and to prosper the modest. And men also hate fullness and love the modest. The destinies of men are subject to immutable laws that must fulfil themselves. But man has it in his power to shape his fate, according as his behaviour exposes him to the influence of benevolent or of destructive forces. When a man holds a high position and is nevertheless modest, he shines with the light of wisdom; if he is in a lowly position and is modest, he cannot be passed by. Thus the superior man can carry out his work to the end without boasting of what he has achieved. “Out of the fullness of the heart the mouth speaketh.” When a man’s attitude of mind is so modest that this expresses itself in his outward behaviour, it is a source of good fortune to him. For the possibility of exerting a lasting influence arises of itself, and no one can interfere. The pushing upward of the good elements encounters no obstruction and is therefore accompanied by great success. The pushing upward is made possible not by violence but by modesty and adaptability. Since the individual is borne along by the propitiousness of the time, he advances. He must go to see authoritative people. He need not be afraid to do this, because success is assured. But he must set to work, for activity (this is the meaning of “the south”) brings good fortune.