Shih Ho indicates successful progress (in the condition of things which it supposes). It will be advantageous to use legal constraints.
Commentary on the Judgment
頤中有物，曰噬嗑，噬嗑而亨。剛柔分，動而明，雷電合而章。柔得中而上行，雖不當位，利用獄也。
The existence of something between the jaws gives rise to the name Shih Ho (Union by means of biting through the intervening article).
The Union by means of biting through the intervening article indicates 'the successful progress (denoted by the hexagram).' The strong and weak (lines) are equally divided (in the figure). Movement is denoted (by the lower trigram), and bright intelligence (by the upper); thunder and lightning uniting in them, and having brilliant manifestation. The weak (fifth) line is in the centre, and acts in its high position. Although it is not in its proper position, this is advantageous for the use of legal constraints.
The Image
雷電噬嗑；先王以明罰敕法。
(The trigrams representing) thunder and lightning form Shih Ho. The ancient kings, in accordance with this, framed their penalties with intelligence, and promulgated their laws.
爻辭 The six lines
When one line moves, the hexagram becomes another:
上九Nine at the top
何校滅耳，凶。
The sixth line, undivided, shows one wearing the cangue, and deprived of his ears. There will be evil.
Its symbolism
何校滅耳，聰不明也。
'He wears the cangue and is deprived of his ears:'—he hears, but will not understand.
The fifth line, divided, shows one gnawing at dried flesh, and finding the yellow gold. Let him be firm and correct, realising the peril (of his position). There will be no error.
Its symbolism
貞厲无咎，得當也。
'Let him be firm and correct, realising the peril (of his position), and there will be no error:'—he will possess every quality appropriate (to his position and task).
The fourth line, undivided, shows one gnawing the flesh dried on the bone, and getting the pledges of money and arrows. It will be advantageous to him to realise the difficulty of his task and be firm,—in which case there will be good fortune.
Its symbolism
利艱貞吉，未光也。
'It will be advantageous to him to realise the difficulty of his task and be firm, in which case there will be good fortune:'—his light has not yet been sufficiently displayed.
The third line, divided, shows one gnawing dried flesh, and meeting with what is disagreeable. There will be occasion for some small regret, but no (great) error.
Its symbolism
遇毒，位不當也。
'He meets with what is disagreeable and hurtful:'—his position is not the proper one for him.
Shown in the classical Chinese with James Legge's English (1882).
Questions about this hexagram
What does Hexagram 21, Biting Together, mean?
Thunder and lightning: jaws closing on an obstacle. Something is in the way and must be bitten through — favourable for administering justice.
Which trigrams form Biting Together?
離 above 震 — fire over thunder. Its nuclear hexagram (lines 2–5) is 蹇 Impasse.
What happens when a line of Biting Together changes?
A moving line turns the hexagram into another one; the list above shows all six. With several moving lines, the guide to changing lines explains which text to read.
How do I get Biting Together in a reading?
Build six lines from the bottom up with three coins or yarrow stalks; the pattern — - - - - — - - — is Biting Together. You can also cast a reading here — the lines are decided by code, the text is this page's.