"It is possible, brahman, to lay down a gradual training, a gradual doing, a gradual practice in respect of this dhamma and discipline, Brahman, even a skilled trainer of horses, having taken on a beautiful thoroughbred first of all gets it used to the training in respect of wearing the bit. Then he gets it used to further training — even so brahman, the Tathagata, having taken on a man to be tamed, first of all disciplines him thus:
"'Come you, monk, be of moral habit, live controlled by the control of the Obligations, endowed with [right] behavior and posture, seeing peril in the slightest fault and, undertaking them, train yourself in the rules of training.' As soon, brahman, as the monk is of moral habit, controlled by the control of the Obligations, endowed with [right] behavior and posture; seeing peril in the slightest fault and, undertaking them, trains himself in the rules of training, the Tathagata disciplines him further saying:
[Here the Buddha moves on to each subsequent aspect of this gradual training after the previous one has been reasonably perfected, illustrating how the Dhamma can be seen and taught as a "gradual training, gradual doing, gradual practice in respect of this dhamma and discipline."]
(For other suttas similar to this, see AN 3.8, AN 3.85, AN 3.86, Snp 4.15, Ud 5.5 , etc. )
Beyond that, my own personal approach towards, and understanding of, the precepts is that they're things we voluntarily take on because we believe that there's something skillful about doing so, and which we're encouraged to observe to the best of our ability. They constitute the basic level of virtue the Buddha advises is necessary for the peace of mind conducive to a successful practice, especially in regard to meditation, and they're seen as gifts "that are not open to suspicion, will never be open to suspicion, and are unfaulted by knowledgeable contemplatives & priests" (AN 8.39).
As such, I don't see them as being equivalent to commandments dictated by a higher power and/or authority, but more as ethical guidelines. In essence, these precepts are undertaken to protect oneself, as well as others, from the results of our unskillful actions. Hence the underlying principles behind Buddhist ethics are kamma — the idea that certain actions produce pleasant, painful, or neutral feelings/results — and the principle of ahimsa or harmlessness. Essentially, Buddhist ethics revolve around seeing our desires for happiness and freedom from pain in all living creatures (SN 3.8). Nevertheless, Buddhism is ultimately a type of 'religious individualism' in that the teachings on kamma focus on individual actions and their consequences, so ethics are more or less a personal matter that each individual must explore and develop on their own; although guidance is certainly advised.
And all of this helps to inform my opinion that Buddhist ethics aren't entirely black or white, i.e., they aren't seen in terms of ethical and unethical as much as skillful and unskillful. In Buddhism, all intentional actions are understood to have potential consequences, and actions that cause harm to others and/or ourselves are considered to be unskillful and something to be avoided. But the Buddha never condemns people merely for making unskillful choices or breaking the precepts; he simply urges them (albeit with strong language sometimes) to learn from their mistakes and to make an effort to renounce their unskillful behaviour with the understanding that skillful behaviour leads to long-term welfare and happiness.
Certainly our adherence to the precepts will improve in the course of our practice, and skillful actions (done out of non-greed, non-hatred, and non-delusions) are morally superior (i.e., more beneficial, wholesome, and conducive to pleasure and happiness) than unskillful ones; but we're not expected to be perfect in our morality right away. As the Buddha explains in AN 9.7, only one "whose mental fermentations are ended, who has reached fulfillment, done the task, laid down the burden, attained the true goal, totally destroyed the fetter of becoming, and who is released through right gnosis [i.e., an arahant], cannot possibly transgress these five principles." At that point, they're no longer precepts, but a natural part of our being.
And I can't speak for anyone else, but I still have a long way to go before I'm completely incapable of transgressing any of the precepts, which is why I just find it more useful to view the precepts as training rules, guidelines, etc. that I do my best to adhere to and follow while on the gradual path towards nibbana and moral perfection than commandments inviolably set in stone. It's certainly better not to break them. But if I happen to break one, instead of condemning myself and inflicting additional suffering on top of that already conditioned by my unskillful action, I simply have to acknowledge the breach and carry on with my practice, striving not to make the same mistakes in the future.
