"Civil Disobedience" by Henry David Thoreau is one of the most famous essays ever written on a person's duty to follow their conscience rather than blindly follow the government in matters that involve moral choices. Such world changers as Mahatma Gandhi, Leo Tolstoy, and Martin Luther King, Jr., were influenced by Thoreau's thoughts. In the essay, Thoreau writes that "Under a government that imprisons any unjustly, the true place for a just man is also a prison." He illustrates this by recounting how he once went to prison for refusing to pay the poll tax, concerned that the tax might somehow be used in the support of slavery. He adds that he doesn't mind paying the highway tax, which benefits himself and his neighbors. In other words, a person must be free to follow his conscience and not government dictates in moral matters.

As for the rich, Thoreau is critical of them because the wealth and material goods that they have accumulated cause them to compromise their integrity and moral values. This would make them follow government directives rather than their consciences when they make moral decisions. He writes:

If there were one who lived wholly without the use of money, the state would hesitate to demand it of him. But the rich man--not to make any invidious comparison--is always sold to the institution which makes him rich. Absolutely speaking, the more money, the less virtue; for money comes between a man and his objects, and obtains them for him, and it was certainly no great virtue to obtain it.

Thoreau goes on to say, speaking of a rich person in general, because he is so dependent on his money, "Thus his moral ground is taken from under his feet." Thoreau claims that the only way a rich man can make wise decisions is to "carry out those schemes which he entertained when he was poor." As for how Thoreau's views of materialism compare to today's world, they are as relevant and true now as they ever were.

Thoreau feels that the rich have essentially sold themselves to whatever it is that has made them rich. Their wealth, and their materialist desire to retain that wealth and everything it buys, corrupts them. They will not act to preserve whatever is virtuous; they will, instead, act to preserve the thing that increases and maintains their wealth. To this end, he says,

[...] the rich man [...] is always sold to the institution which makes him rich. Absolutely speaking, the more money, the less virtue; for money comes between a man and his objects, and obtains them for him; and it was certainly no great virtue to obtain it. It puts to rest many questions which he would otherwise be taxed to answer; while the only new question which it puts is the hard but superfluous one, how to spend it. Thus his moral ground is taken from under his feet.

In a sense, then, possessing wealth changes one's priorities. Instead of privileging virtue and the moral right, one learns to privilege money. One will not rock the boat as long as the metaphorical boat is profitable. For Thoreau, the more money one acquires, the less virtuous one becomes. The rich begin only to concern themselves with how to spend their money rather than how to do good in the world. For example, the rich may be loathe to oppose the government, even when that government is unjust, because they fear the seizure of their property. Moreover, Thoreau argues that

The best thing a man can do for his culture when he is rich is to endeavor to carry out those schemes which he entertained when he was poor.

If the rich person can remember what priorities and objectives he had as a poor man, then he will be much more helpful to society.

Ultimately, in the twenty-first-century, I think many people place a high premium on philanthropy. There are a number of millionaires and billionaires who make very large charitable donations every year, and some even have their own foundations to benefit disadvantaged populations. Thoreau would likely counter, however, that just because they are making donations doesn't mean they are behaving virtuously. If the rich continue to pay taxes to an unjust government, for example, then their philanthropic contributions seem like little more than lip-service to virtue (similar to the way he viewed people who vote for the right but do nothing else to achieve it). I'm not sure people are any more materialistic now than they were during the mid-nineteenth-century, though I'm sure some people would point to our reliance on technology as evidence that we are. In his essay, Thoreau doubts the morality of the rich, just as many people doubt the morality of the rich nowadays. Whether his criticism is justified is, of course, up to the individual.