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"The Prince" is a practical guide for ruling a country. The general theme of "The Prince" is the acceptance that the aims of rulers, such as glory and power, can justify the use of immoral means to achieve these ends.
Only the expenditure of one’s own resources is harmful; and, indeed, nothing feeds upon itself as liberality does. The more it is indulged, the fewer are the means to indulge it further. As a consequence, a prince becomes poor and contemptible or, to escape poverty, becomes rapacious and hateful. Of all the things he must guard against, hatred and contempt come first, and liberality leads to both. Therefore it is better to have a name for miserliness, which breeds disgrace without hatred, than, in pursuing a name for liberality, to resort to rapacity, which breeds both disgrace and hatred.
This quote is found in Chapter 16 of "The Prince". Machiavelli advises the prince to disregard the traditional principles of virtue because these principles will ultimately be detrimental to the prince's ability to rule.