1. For the better understanding of the first four books of this work, it is to be observed that what I distinguish by the name of virtue, in a republic, is the love of one's country, that is, the love of equality. It is not a moral, nor a Christian, but a political virtue; and it is the spring which sets the republican government in motion, as honour is the spring which gives motion to monarchy. Hence it is that I have distinguished the love of one's country, and of equality, by the appellation of political virtue. My ideas are new, and therefore I have been obliged to find new words, or to give new acceptations to old terms, in order to convey my meaning. They, who are unacquainted with this particular, have made me say most strange absurdities, such as would be shocking in any part of the world, because in all countries and governments morality is requisite.
2. The reader is also to notice that there is a vast difference between saying that a certain quality, modification of the mind, or virtue, is not the spring by which government is actuated, and affirming that it is not to be found in that government. Were I to say such a wheel or such a pinion is not the spring which sets the watch going, can you infer thence that they are not to be found in the watch? So far is it from being true that the moral and Christian virtues are excluded from monarchy, that even political virtue is not excluded. In a word, honour is found in a republic, though its spring be political virtue; and political virtue is found in a monarchical government, though it be actuated by honour.
To conclude, the honest man of whom we treat in the third book, chapter 5, is not the Christian, but the political honest man, who is possessed of the political virtue there mentioned. He is the man who loves the laws of his country, and who is actuated by the love of those laws. I have set these matters in a clearer light in the present edition, by giving a more precise meaning to my expression: and in most places where I have made use of the word virtue I have taken care to add the term political.
赏析：孟德斯鸠为了使读者对本书前四个章节的理解更加准确，首先对书中所提的美德给出解释。此美德不同于世俗逻辑的美德，即道德意义上的美德；也不同于宗教中所宣扬的美德，即基督教教义上的美德。孟德斯鸠所谓的美德，是一种政治美德，而在共和国这个范畴里，政治美德又具体为热爱祖国和崇尚平等。对此，孟德斯鸠给出了原因：美德是共和政体不断完善的原动力。面对不甚了解却盲目质疑的人，孟德斯鸠接着又解释到这只是给旧词一个新的理解，从而更好表达他的一些新见解。
为了避免读者把某种品质、意识形态不是驱动某种政体的原动力等同于某种政体中就不存在这种原动力，孟德斯鸠明确指出这两者是毫不相干的。随后他用一个极其生动浅显、众所周知的例子来说明，即钟表中内有齿轮，可这个齿轮却不一定是钟表的原动力。由此可知，尽管在某种政体里政治美德德是原动力，荣誉依然存在；或者在某种政体里，虽然存在政治美德，但是它的原动力依旧是荣誉。
孟德斯鸠最后指出第三章提及的“善人”，并不是基督教教义上所赞颂的善人，而是具有政治美德的人。这些人的所作所为皆源于对国家法律的热爱。因此，在《论法的精神》中提及“美德”的地方，孟德斯鸠都替以“政治美德”。
