The laws of conscience, which we pretend to be derived from nature, proceed from custom; every one, having an inward veneration for the opinions and manners approved and received among his own people, cannot, without very great reluctance, depart from them, nor apply himself to them without applause.

[Les loix de la conscience, que nous disons naistre de nature, naissent de la coustume : chacun ayant en veneration interne les opinions & mœurs approuvees & receues autour de luy, ne s’en peut desprendre sans remors, ny s’y appliquer sans applaudissement.]

Michel de Montaigne (1533-1592) French essayist

Essays, Book 1, ch. 22 (1.22), “Of Custom and Not Easily Changing an Accepted Law [De la Coustume et de Ne Changer Aisément une Loy Receüe]” (1572) [tr. Cotton/Hazlitt (1877)]
    (Source)

The essay was in the 1st (1580) edition, but this passage was written in or after 1588, showing up in the final (1588) edition.

Some translators use the 1588 sequence of chapters, not the 1595, and so identify this as ch. 23.

(Source (French)). Alternate translations:

The lawes of conscience, which we say to proceede from nature, rise and proceede of custome: every man holding in speciall regard, and inward veneration the opinions approved, and customes received about him, can not without remorse leave them, nor without applause applie himselfe unto them.
[tr. Florio (1603)]

The Laws of Conscience, which we pretend to be deriv’d from Nature, proceed from Custom; every one having an inward Veneration for the Opinions and Manners, approv’d and receiv’d amongst his own People, cannot without very great Reluctancy depart from them, nor apply himself to them without applause.
[tr. Cotton (1686)]

The laws of conscience, which we say are engendered by nature, are born of custom; every man, holding in inward veneration the opinions and fashions approved and received around him, can not depart from them without [self] upbraiding, or conform to them without [self] commendation.
[tr. Ives (1925), 1.23]

The laws of conscience, which we say are born of nature, are born of custom. Each man, holding in inward veneration the opinions and the behavior approved and accepted around him, cannot break loose from them without remorse, or apply himself to them without self-satisfaction.
[tr. Frame (1943), 1.23]

The laws of conscience which we say are born of Nature are born of custom; since man inwardly venerates the opinions and the manners approved and received about him, he cannot without remorse free himself from them nor apply himself to them without self-approbation.
[tr. Screech (1987), 1.23]