chiasmus: A rhetorical or literary figure in which words, grammatical constructions, or concepts are repeated in reverse order, in the same or a modified form; inversion in the second of two parallel forms.
But O, what damned minutes tells he o’er
Who dotes, yet doubts; suspects, yet strong loves.
antimetabole: the repetition of words or ideas in successive clauses, but in transposed grammatical order.
Ask not what your country can do for you; ask what you can do for your country. –JFK
Milton, Upon the Circumcision:
O more exceeding love or law more just?
Milton, Paradise Lost:
The law of God exact he shall fulfill
Both by obedience and by love though love
Alone shall fulfill the law…