“Any law too often subject to infraction is bad; it is the duty of the legislator to repeal or change it.”

John Grisham, The Last Juror: A Novel, p. 357 (Author's Note) (2004)
Source: [Grisham, John, 2004, The Last Juror, BCA, 357 (Author's Note), 0-385-51043-8]

Address at Cornell College, Mount Vernon, Iowa (15 October 1962) https://news.cornellcollege.edu/dr-martin-luther-kings-visit-to-cornell-college/; also quoted in Wall Street Journal (13 November 1962), Notable & Quotable , p. 18
Variant:
It is true that behavior cannot be legislated, and legislation cannot make you love me, but legislation can restrain you from lynching me, and I think that is kind of important.
Address at Finney Chapel, Oberlin College (22 October 1964), as reported in "When MLK came to Oberlin" by Cindy Leise, The Chronicle-Telegram (21 January 2008)
1960s

1860s, First Inaugural Address (1869)
Context: Laws are to govern all alike — those opposed as well as those who favor them. I know no method to secure the repeal of bad or obnoxious laws so effective as their stringent execution.

Strategic objectives of new Government (May 23, 2007)

1760s, A Dissertation on the Canon and Feudal Law (1765)
Context: The poor people, it is true, have been much less successful than the great. They have seldom found either leisure or opportunity to form a union and exert their strength; ignorant as they were of arts and letters, they have seldom been able to frame and support a regular opposition. This, however, has been known by the great to be the temper of mankind; and they have accordingly labored, in all ages, to wrest from the populace, as they are contemptuously called, the knowledge of their rights and wrongs, and the power to assert the former or redress the latter. I say RIGHTS, for such they have, undoubtedly, antecedent to all earthly government, — Rights, that cannot be repealed or restrained by human laws — Rights, derived from the great Legislator of the universe.

Statement (1835), as quoted in Andrew Johnson, Plebeian and Patriot (1928) by Robert Watson Winston.
Quote

Principles of Legislation (1830), Ch. X : Analysis of Political Good and Evil; How they are spread in society
Context: It is with government, as with medicine. They have both but a choice of evils. Every law is an evil, for every law is an infraction of liberty: And I repeat that government has but a choice of evils: In making this choice, what ought to be the object of the legislator? He ought to assure himself of two things; 1st, that in every case, the incidents which he tries to prevent are really evils; and 2ndly, that if evils, they are greater than those which he employs to prevent them.
There are then two things to be regarded; the evil of the offence and the evil of the law; the evil of the malady and the evil of the remedy.
An evil comes rarely alone. A lot of evil cannot well fall upon an individual without spreading itself about him, as about a common centre. In the course of its progress we see it take different shapes: we see evil of one kind issue from evil of another kind; evil proceed from good and good from evil. All these changes, it is important to know and to distinguish; in this, in fact, consists the essence of legislation.

1 St. Tr. (N. S.) 484.
Trial of Hunt and others (King v. Hunt) (1820)

Compromise proposal http://www.civilwarcauses.org/comp.htm#Jefferson%20Davis%20of%20Mississippi (24 December 1860)
1860s