The rules of the vinaya are much too complex for us to deal with here, but we can get a sense of them by looking at the so-called Ten Precepts. The classic way of expressing them is as follows. (See Noss, 165, for a slightly different rendition. Note also that the laity are bound to only a less strict form of the first 5 precepts.)
1. Taking life (ahimsa).
2. Taking what is not given.
3. Sexual misconduct.
4. Lying and deception.
5. Drinking liquor.
6. Eating after noon.
7. Observing dancing, singing, and other entertainments.
8. Wearing garlands, scents, unguents, or ornaments.
9. The use of high beds.
10. Accepting gold and silver (i.e., money).
The rules of discipline that govern the behavior of monks are much more complex
than those listed in the Ten Precepts, just as the legal requirements in the
Torah are much more elaborate and subtle than the 10 Commandments. There are
many specific requirements about eating, sleeping, interactions between bhikshus
and bhikshunis (monks and nuns), sexual behavior, and so forth. The elaborate
nature of these codes was necessary for the regulation of monastic life, especially
after the time when many monks began to live together in monasteries sometime
after the death of the Buddha. It is not important for us to consider these
details. It is more important to understand the nature of shila ("ethics"
or "proper behavior") from within Buddhism. The ideas contained within the 10
Precepts can help us to understand this quite clearly.
First, consider the difference between the form of the 10 Precepts, as opposed to the 10 Commandments. The 10 Commandments are of the form "Thou shalt do x", or "Thou shalt not do y". Biblical scholars have determined that the form of these "commands" go back to simple societies in which specific forms of behavior were either prescribed or proscribed (required or prohibited), and violation of these rules would bring negative sanctions from the group, particularly those who were in authority. In the theological contexts of ancient Israelite religion, and in later Judaism, Christianity, and Islam, it was usually understood that following the dictates of the law would bring blessings from God, and that violations would bring punishments. Thus, there is implicit within most ethical systems from Abrahamic tradition the idea that morality stems from the commands of God who enforces the Divine will on human beings, or that people have an obligation to society to behave in certain ways.
However, within the 10 Precepts note that the form of each Precept is "Refrain from x." On a very general level, it seems that the Buddhist code is saying the same thing as the Abrahamic, namely "Do this, Don't do that". However, at a deeper level the difference is profound. In Buddhism the Noble 8-Fold path is in essence a set of recommendations for structuring one's life that will eventually lead to enlightenment and the cessation of suffering. Within Buddhism there is no stress whatsoever laid on the existence of an omnipotent God who enforces his moral will upon humans, depending on whether they have followed his will. Instead, since Buddhism (like Hinduism) is governed by the laws of Karma and Samsara, there is simply a notion of cause and effect: if you lead your life in one way, there will be a certain sort of outcome. If you lead your life in another way, there will be another sort of outcome. The 10 Precepts (in short form) outline the sorts of things that one should do in order to overcome suffering by eliminating desire. If a person chooses to follow another path, it might be the case that suffering can be overcome in that way. (Buddhism does not assert that it is the only true path, though generally it asserts that it is the best path.) In general, however, Buddhists would contend that if people do not regulate their behavior according to principles like those outlined in the 10 Precepts, then desire will not diminish, and suffering will not abate.
A simple way of understanding the 10 Precepts is to think of them as the basic rules of a training program for spiritual fitness. If you wanted to be a great body builder, you'd be well advised to follow the leadership of someone like Arnold Schwartzenegger. He was Mr. Universe. He was one of the best. He has proven himself to be a master of that art, and if he were your personal trainer, he'd be able to take you a long way towards sculpted beauty. That is, he would, if you were willing to follow his advice. However, if he advised you to do 100 reps in ten different excercises with free weights per day, and you only did 10, you shouldn't be surprised when you continue to look like a weenie. Or, if he told you to lay off the ice cream and cherry pie, but you didn't, you'd hardly be surprised to discover that you continue to look like a banana split. Arnold would probably tell you that you get what you put into it. If you follow his recommendations, you'll be able to expect a certain outcome. If you don't, then another outcome is likely to be guaranteed as well. And you, as the individual body builder, have to take responsibility for the body you want to have. Furthermore, I don't think that Arnold would judge you harshly for eating a quart of ice cream every night. (He'd probably introduce a line for sale through Planet Hollywood.) "It's your life; you make what you want out of it," he'd probably say, in his cute Austrian accent.
By analogy, the Buddha can be understood as one of the great spiritual body builders of all time. The Buddha proved his own ability at spiritual development through the things he accomplished in his own practice, and he recommended a particular path that one can follow in order to get the sorts of results that he himself (the Buddha) achieved. If one follows the recommendations that the Buddha makes, the outcome will be what he suggests: the elimination of desire and suffering. If a person does not follow these recommendations, then the result is likely to be the opposite: the inflaming of the passions with a corequisite increase in suffering. The choice is up to every individual person. The outcome is dictated by the laws of the cosmos (particularly, karma), and individuals have to accept responsibility their own choices. But it's not really a question of judgement or punishment.
The 10 Precepts, when understood in this light, are really a very interesting way of discussing "ethics". The way that we understand "ethics" in the West usually has to do with either maintaining good relations with God, or in maintaining good and proper relations with other people. If one treats others well, then one is an ethical person. However, the fundamental principle governing Buddhist ethics has to do with the governing principles of the 4 Noble Truths. Those things that define "proper behavior" are those that will reduce desire so as to eliminate suffering.
Consider, for example, the First Precept, "Refrain from Taking Life". This looks like "Thou Shalt Not Kill" from the Ten Commandments, and in the Ten Commandments the focus is on the obligations that a person owes to God and to the other people in the community. However, in Buddhist thinking the primary operative principle is that by killing others one does injury to one's self. It is a "bad" thing to do because of the "bad karma" that one heaps on one's self. So, I believe, the First Precept needs to be considered in the following way.
Reflect on the circumstances in which we would be likely to kill another sentient being -- this includes all sentient creatures, humans, other mammals, fish, birds, and insects. Why would we want to kill? In nearly every circumstance that I can imagine, we would choose to kill another creature in order to satisfy some craving of our own. Those of us who eat meat, for example, do so because we believe it tastes good and because it satisfies (temporarily) our hunger. However, when we reflect on the suffering we must inflict upon another being in order to satisfy our own desires, the level of our willful ignorance rapidly springs to consciousness. If we consider, for example, the meat industry in the United States, with its confinement feeding (of cattle, hogs, chickens, and other animals) where animals spend their whole lives in cramped quarters suspended over their own waste without ever stepping into the sun... If we consider the way that they are transported to packing plants, which are slaughter houses flowing with blood and drowning in screams of horror from the animals being herded towards their deaths by men in rubber suits... If we were to consider these images seriously with every meaty meal we ate, would most of us actually be able to enjoy these meals? My brother has frequently been accused of very bad manners by bringing up the topic of packing plants at steak dinners, so that everyone at the table would appreciate their responsibility for the sufferings of the animals whose flesh they are about to eat. The natural revulsion that most people feel for the suffering of others is a clear indicator that we indulge our own desire for meat by being willfully ignorant of the pain and suffering that we inflict on other beings. But according to Buddhist principles the first thing we should think about is how maintaining this sort of willful ignorance affects our own state and increases our suffering. Approaching the problem of proper behavior is not really a "selfish" view, since the goal of Buddhism is to bring about an awareness of "anatman/anatta" (no-self). Moreover, the outcome of developing a clear sense of ahimsa would be a profound sense of compassion for other sentient beings in the midst of their suffering. Still, the logic of the Buddhist conceptual and behavioral system begins with the individual's own awareness of suffering in the first person and the practical requirements for overcoming the suffering that we experience ourselves. It is not obedience to a law of compassion, it is a requirement of a system of training that enables anyone and everyone to lead a better life.
This same principle applies to the lives of sentient beings in general. Why do we swat mosquitos that buzz around our ears and land on our cheeks? Because the presence of the mosquito is annoying, and we want to eliminate the object that frustrates our desire for comfort. But isn't this the height of selfishness, and the opposite of a clear awareness of the truths articulated in the 3 Flaws? If we want to make spiritual progress ourselves, we would want to see, according to basic Buddhist teachings, the degree to which our own desires and aversions are obstacles to seeing clearly the suffering of ourselves and others.
This basic insight also informs the rest of the 10 Precepts. Considering again both the fact that the 10 precepts (as stated) are intended for monks, and the contrast with the 10 commandments, you should be able to see the profound nature of the difference between the two systems. The 2nd Precept "Refrain from taking what is not given" is not the same as "Thou Shalt Not Steal". The 2nd Precept also "forbids" earning anything. When we work at jobs, we are (usually) not stealing from others. But earning a living would violate the 2nd Precept for a simple, but subtle reason: if a person is earning (that is, working in order to be paid), then the work is itself motivated by desire, and the act of earning inflames the passion of desire by gratifying it, by structuring one's life around the quest for the objects of desire. In monastic practice in Buddhist countries, monks do not actually "beg" for alms from the lay community, but they "present themselves" for alms. That is, monks present themselves at doorsteps of private homes, at the counters of stores and shops, to individuals on the street, with eyes downturned, standing with a bowl for receiving alms in their hands. They ask for nothing. If alms are given, they give no thanks. If alms are not given, there is to be no resentment or recrimination. Monks merely present themselves for alms because monks need food to live while they pursue spiritual discipline. But, since they are not actually "asking for" alms, there is no thanks to be given and no resentment to be harbored. In this way, desire is removed from the equation, as is the gratification of desire and its frustrations. It promotes behavior that eliminates desire generally.
Consider also the Precepts concering liquor (and drugs), entertainments, and garlands, scents, and unguents. These are not Puritanical prohibitions in the sense that they are seen to be "bad", as violations of God's rule and decency to the community. Rather, they all have to do with the gratification of desire. Why do we drink or do drugs? To change our perception away from world we normally live in, to another that we think will be more fun. We "drug ourselves" in order to escape the pain of daily life. But, according to Buddhist analysis, does this really help, or is it more like heaping coal on the fire? Entertainments are really no different, are they? Why do we go to the movies, or listen to favorite music? To make us experience the world in a way that will please us. Even if you like to listen to Tammy Wynette sing about her D-I-V-O-R-C-E, it's probably because you want to indulge yourself in the sweet feelings of intense sorrow. But this again is a gratification of desire by an external object. The more you do it, the more you're caught in the trap. Why do we wear perfume? Why do we put lotions on our skin? Why do we wear flowers? All for the same reason. It is said that early Buddhist monks were allowed to use cow's urine and a dog's lick to help them heal wounds. Such things (due to their curative powers) are necessary for good health. Buddhism is the Middle Way. But the use of Coppertone to help with the perfect tan is an indulgence of desire.
And High Beds? What better way to gratify one's desires than to crawl into a warm and cozy bed at night and sleep away your cares?
Gold and Silver? According to the principles of the Vinaya, those posessions of monks are limited to the things needed for the maintenance of life. Before the founding of the first monasteries, monks were limited to the following possessions: a robe, a bowl for alms, and a razor for shaving the head. The sorts of things that one was to receive for alms would be limited to the food that was needed for the day. If one were to receive money as alms, this would not (strictly speaking) be a violaton of the 2nd Precept, because it would be given. However, since money can be stored away for later use, it could lead to a sense of reliance on external objects for one's peace of mind ("Well, this monk thing is ok for a while, but maybe I'd better have a little something tucked away for a new Porsche, in case I change my mind later."), and is therefore to be avoided.
As a matter of fact, once Buddhist monasteries were formed and kings began to make donations of land, buildings, and precious things (like gold, silver, and jewels), there was a huge controversy among members of the Sangha (the community of Buddhist monks) about whether this was appropriate. Those who said it was ok for monasteries to accept these gifts eventually won out, as is clear from the funding of Buddhist institutions around the world today. But one must wonder about whether the Buddha himself originally intended for Buddhist institutions to operate in this way. Still, how strictly one must adhere to the rules of the Vinaya is a topic of great importance, and it is one that helps to distinguish the Theravada from the Mahayana traditions of Buddhism.