There is in the soul of every man, something naturally soft, low, enervated in a manner, and languid. Were there nothing besides this, men would be the greatest of monsters; but there is present to every man reason, which presides over, and gives laws to all; which, by improving itself, and making continual advances, becomes perfect virtue.

[Est in animis omnium fere natura molle quiddam, demissum, humile, enervatum quodam modo et languidum. Si nihil esset aliud, nihil esset homine deformius. sed praesto est domina omnium et regina ratio, quae conixa per se et progressa longius fit perfecta virtus.]

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

Tusculan Disputations [Tusculanae Disputationes], Book 2, ch. 21 (2.21) / sec. 47 (45 BC) [tr. Yonge (1853)]
    (Source)

(Source (Latin)). Alternate translations:

There is in the Souls of all men, in a manner, naturally somewhat lasche, mean, low-spirited, in a sort emasculate and feeble; were there nothing else, man would be the most deformed thing in the World; but Reason the Lady and Empress of all things, is at hand to help; which bearing up on her own strength, and advancing farther, becometh, at length, accomplish'd Vertue
[tr. Wase (1643)]

Every soul of man has naturally something soft, low, enervated in a manner, and languid. Were there nothing besides this, men would be the greatest of monsters; but there is present to every man reason, which presides and gives law to all, which by improving itself, and making continual advances, becomes perfect virtue.
[tr. Main (1824)]

There is, in the minds of nearly all men, by nature, something soft, abject, low, enervated somehow, and languid, doting. If this were all, nothing were more disgusting than man. But there is also the mistress and queen of all things, reason, who, supported by herself, and after long progress, becomes perfect virtue.
[tr. Otis (1839)]

There is naturally in the soul of almost every man something soft, low, earthy, in a certain degree nerveless and feeble. But reason is at hand, mistress and queen of all, which by its own force striving and advancing upward, becomes perfect virtue.
[tr. Peabody (1886)]

There is in practically everybody's souls by nature something soft, lowly, abject, nerveless so to speak, and feeble. If there were nothing else, a human being would be the ugliest thing that exists. But at hand is the mistress and queen of all, Reason, which through its own strivings advances forward and becomes perfected virtue.
[tr. Douglas (1990)]

Nature has seen to it that there is in the souls of virtually all people an element of softness, of lowliness, of the abject, of, as it were, what is nerveless and feeble. If he possessed nothing beyond this, man would be the most hideous of all creatures; but at his side stands reason, the mistress and queen of all, who through striving by her own strength and forging onward becomes perfected virtue.
[tr. Davie (2017)]