The Highest good (n.) is all that can make us worthy of being, ourselves, the final purpose of creation.
The Highest good (n.) is happiness in proportion to worthiness to be happy — an end the moral law commands us to pursue, though nature alone can never join the two.
Highest good (n.) needs a supreme intelligence behind it, not to make morality binding, but to keep it from being a mere ideal that exists nowhere.
The Highest good (n.) is the whole object of a pure will but never its motive: take it as the determining ground before the moral law and you get heteronomy.
The Highest good (n.) was where the ancients staked their whole moral inquiry, openly betraying their mistake; the moderns, having dropped the question, hide the same mistake behind indeterminate words.
The Highest good (n.) rules the realm of grace: the world seen as rational beings under moral laws, where all happiness awaits us unless we ourselves limit our share by unworthiness.
The Highest good (n.) hides an ambiguity: "highest" can mean supreme (the unconditioned condition — virtue) or complete (the whole — virtue crowned with happiness in proportion).
The Highest good (n.) is the ideal of a morally perfect will joined with highest blessedness, cause of all happiness exactly proportioned to worthiness — and only in it can reason ground the hope that being good and being happy will meet.