What this hexagram is about
Thunder high in the heavens, mighty in sound and force — the image of great strength, the firm at its height. The stronger one is, the more one must keep to propriety and self-restraint: do nothing contrary to right, be powerful yet never act rashly — for to lean on sheer force is easily to break.
The Judgment 卦辞
利贞。
Favorable to persevere.
The Image 大象传
《象》曰：雷在天上，大壮；君子以非礼弗履。
Thunder high in the heavens; so the noble person sets no foot where propriety forbids.
Commentary on the Lines 小象传
壮于趾，其孚穷也。
Power showing in the toes — such confidence comes to a dead end.
The Six Lines (hover over the figure above)
Nine at the top羝羊触藩，不能退，不能遂，无攸利，艰则吉。
The ram butts the hedge and can neither draw back nor push through — nothing to gain; yet if one bears the hardship with careful self-possession, good fortune can still come.
Six in the fifth place丧羊于易，无悔。
To lose the ram easily at the field's edge — shedding the excess of one's hardness; there is no remorse.
Six in the fourth place贞吉悔亡，藩决不羸，壮于大舆之輹。
Hold to the right and there is good fortune, and remorse fades; the hedge is broken open and the horns no longer caught — a strength fit and sound, like the stout axle of a great wagon.
Nine in the third place小人用壮，君子用罔，贞厉。羝羊触藩，羸其角。
The small-minded make a show of their strength; the noble person does not lean on it, treating his own force as if it were nothing — for the worth lies in self-restraint. To rely on strength and hold to that brings danger: like a ram that butts the hedge and gets its horns caught fast.
Nine in the second place贞吉。
To hold to what is right — good fortune.
Initial Nine壮于趾，征凶，有孚。
Strength in the toes — forcing it from below, rushing ahead; to go forward brings misfortune, though the intent is sincere.