Still, I do not mean to find fault with the accumulation of property, provided it hurts nobody, but unjust acquisition of it is always to be avoided.

[Nec vero rei familiaris amplificatio nemini nocens vituperanda est, sed fugienda semper iniuria est.]

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

De Officiis [On Duties; On Moral Duty; The Offices], Book 1, ch. 8 (1.8) / sec. 25 (44 BC) [tr. Miller (1913)]
    (Source)

(Source (Latin)). Alternate translations:

Not but that a moderate desire of riches, and bettering a man's estate, so long as it abstains from oppressing of others, is allowable enough; but a very great care ought always to be taken that we be not drawn to any injustice by it.
[tr. Cockman (1699)]

The enlargement of fortune is blameless, while no man suffers by its increase; but injury is forever to be avoided.
[tr. McCartney (1798)]

Nor indeed is the mere desire to improve one's private fortune, without injury to another, deserving of blame; but injustice must ever be avoided.
[tr. Edmonds (1865)]

Nor, indeed, is the increase of property, without harm to any one, to be blamed; but wrong-doing for the sake of gain is never to be tolerated.
[tr. Peabody (1883)]

Not that we have any fault to find with the innocent accumulation of property; it is the unjust acquisition of it of which we must beware.
[tr. Gardiner (1899)]

Of course, no one should criticize an increase in a family's estate that harms no one else, but it should never involve breaking the law.
[tr. Edinger (1974)]