What this hexagram is about
Thunder and wind sustaining each other — the image of endurance. It speaks of holding on with constancy and standing firm in oneself: keep to the right way and to one's true heart, and do not lightly change course; yet endurance is not rigidity — within the constant there is change.
The Judgment 卦辞
恒，亨，无咎，利贞。利有攸往。
Success. No fault. Favorable to persevere. It is favorable to have somewhere to go.
The Image 大象传
《象》曰：雷风，恒；君子以立不易方。
Thunder and wind, enduring together; so the noble person stands firm and does not change his course.
Commentary on the Lines 小象传
浚恒之凶，始求深也。
The misfortune of forcing constancy too deep — seeking depth too soon.
The Six Lines (hover over the figure above)
Nine at the top振恒，凶。
Restless and unsettled, forever shifting and losing all constancy — misfortune.
Six in the fifth place恒其德，贞，妇人吉，夫子凶。
To hold long and fast to one's virtue: in a wife, such constancy to one course brings good fortune, but in a man, to cling rigidly without sense of when to bend brings misfortune.
Six in the fourth place田无禽。
To hunt and take nothing — out of one's proper place, long holding on without result.
Six in the third place不恒其德，或承之羞，贞吝。
Unable to hold steadfastly to one's own virtue, one may meet disgrace for it; to keep to this brings regret.
Nine in the second place悔亡。
Remorse fades away — holding the center with constancy, the fault dissolves of itself.
Initial Nine浚恒，贞凶，无攸利。
To demand endurance too deeply at the very start, impatient for results; to keep to this brings misfortune, and nothing is gained.