How we cite our quotes: Section.Part (if applicable).Paragraph
Quote #1
What is honorable, what is fair, what is becoming, what is noble, what is generous, takes possession of the heart, and animates us to embrace and maintain it. What is intelligible, what is evident, what is probable, what is true, procures only the cool assent of the understanding; and gratifying a speculative curiosity, puts an end to our researches. (I.7)
Here we have it folks—the perfect summary of Hume's moral theory. Hume isn't down on facts and reason, he just thinks that we use both our head and our heart when making moral judgments. Reason is cool and clinical, which is fine (it never did Sherlock Holmes any harm, right?), but it's our natural sentiment that spurs us on and shapes our ideas about what's right and good.
Quote #2
Extinguish all the warm feelings and prepossessions in favor of virtue, and all disgust or aversion to vice: render men totally indifferent towards these distinctions; and morality is no longer a practical study, nor has any tendency to regulate our lives and actions. (I.8)
So, imagine what it would be like if we didn't use sentiment in our moral judgments. Could we even make moral judgments? Hume suggests that we could discuss morality in theory but it would be detached from real life. In other words, it'd be pretty much useless. It's only when we feel a reaction to virtues/vices that morality comes to life.
Quote #3
Celibacy, fasting, penance, mortification, self-denial, humility, silence, solitude, and the whole train of monkish virtues […] neither advance a man's fortune in the world, nor render him a more valuable member of society; neither qualify him for the entertainment of company, nor increase his power of self-enjoyment? (XI.I.3)
Some philosophers (especially religious ones) may believe that self-denial is a virtue. Even outside philosophy, people sometimes admire those who embark on periods of fasting, silence, or solitude. Hume, however, isn't on board with this idea. In his eyes, these things aren't useful or agreeable to anyone, so how can they be virtues? Hello?