Liberty, after she has been chained up awhile, is always more fierce, and sets her teeth in deeper, than she would otherwise have done if she had never been restrained.

[Acriores autem morsus sunt intermissae libertatis quam retentae.]

Marcus Tullius Cicero (106-43 BC) Roman orator, statesman, philosopher

De Officiis [On Duties; On Moral Duty; The Offices], Book 2, ch. 7 (2.7) / sec. 14 (44 BC) [tr. Cockman (1699)]
    (Source)

(Source (Latin)). Alternate translations:

And the inflictions of freedom interrupted, are more rigorous than if it had been retained.
[tr. McCartney (1798)]

For the inflictions of liberty, when it has been suspended, are more severe than if it had been retained.
[tr. Edmonds (1865)]

Men indeed feel more keenly the suppression of liberty than any evils incident to its preservation.
[tr. Peabody (1883)]

Freedom, if suppressed, only bites with keener fang.
[tr. Gardiner (1899)]

Freedom suppressed and again regained bites with keener fangs than freedom never endangered.
[tr. Miller (1913)]

But the wounds caused by the suspension of freedom hurt worse than those caused by maintaining it.
[tr. Edinger (1974)]