The ninth line occupies the honored position with centrality and correctness, and below it is met with compliant response from centrality and correctness; it can be called the utmost of Innocence, and its Dao cannot be surpassed. Illness represents affliction.
With the innocence of Nine in the Fifth Place, if an illness occurs, do not treat it with medicine and there will be joy.
When a person has an illness, medicines and acupuncture attack and dispel the evil to nurture the upright; but if the body's qi is harmonious and balanced without any inherent disease, attacking and treating it will instead harm one's upright qi.
Therefore, 'do not use medicine and there will be joy'; joy means the illness disappears on its own.
What is called illness in Innocence refers to situations where one governs but they are not governed, leads but they do not follow, transforms but they do not change—where external falsehood becomes an affliction to one's innocence.
Examples include Shun with the Sanmiao, the Duke of Zhou with Guan and Cai, and Confucius with Shusun Wushu. When one is already without falsehood and someone afflicts one, one should remain composed; the afflictions to innocence are not worth worrying about.
If one were to attack and treat oneself, that would be altering one's innocence and shifting into falsehood. Since the fifth line occupies the extreme of Innocence, its only warning is against movement: movement brings falsehood.
The Xiang says: 'The medicine for innocence must not be tested.' When a person has falsehood, principle dictates that it must be amended. But when one is already without falsehood, using medicine to treat it is conversely creating falsehood. How could that be used?
Hence it says 'it must not be tested.' 'Tested' means used temporarily, like saying 'tasted a little.'