What is the law? A thing that ought neither to be swayed by favor, nor be shattered by force, nor be corrupted by power.

[Quod enim est ius civile? Quod neque inflecti gratia neque perfringi potentia neque adulterari pecunia debeat.]

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

Pro Caecina [For Aulus Caecina], ch. 26 / sec. 73 (c. 69 BC) [tr. @sentantiq (2013)]
    (Source)

(Source (Latin)). Other translations:

For, indeed, what is the civil law? A thing which can neither be bent by influence, nor broken down by power, nor adulterated by corruption.
[tr. Yonge (1856)]

How may we describe it? The law is that which influence cannot bend, nor power break, nor wealth corrupt.
[tr. Grose Hodge (Loeb) (1927)]