Any peace, even the most inequitable, should be preferred to the most righteous war.

[Iniquissimam pacem iustissimo bello anteferrem.]

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

Epistulae ad Familiares [Letters to Friends], Book 6, Letter 6, sec. 5 (6.6.5), to Aulus Cæcina (46 BC) [tr. Shuckburgh (1899), #486]
    (Source)

On his efforts to prevent a civil war between Caesar and Pompeius.

(Source (Latin)). Alternate translation:

Peace: the which, though it were accompanied with unequall conditions, yet I preferred it before warre, which on our behalfe was most just.
[tr. Webbe (1620)]

Contests of this kind, tho' ever so justly founded, even the most disadvantageous terms of accommodation were preferable to having recourse to arms.
[tr. Melmoth (1753), 9.34]

Why I would choose the most unfair peace in preference to the fairest of wars.
[tr. Jeans (1880), # 91]

A peace even on the most unfavourable terms was preferable to the most righteous of wars.
[tr. Williams (Loeb) (1928)]

[...] the most inequitable peace as preferable to the most righteous of wars.
[tr. Shackleton Bailey (1978), # 234]

I would prefer the most unfair peace to the justest war.
[tr. @sententiq (2012)]