The Buddhist Precepts are the foundation of Buddhist ethics, practiced by both lay and monastic Buddhists in some form within both Theravada and Mahayana Buddhism. All variations on the Precepts incorporate the core Five Precepts, which are generally translated as:
1. I undertake the training rule to abstain from taking life.
2. I undertake the training rule to abstain from taking what is not given.
3. I undertake the training rule to abstain from sexual misconduct.
4. I undertake the training rule to abstain from false speech.
5. I undertake the training rule to abstain from intoxicating substances that cause heedlessness.
Of course in this form, there is still much left to interpretation. For example, the first Precept, 'to abstain from taking life', is interpreted in varying ways in relationship to the taking of animal life for food. Mahayana Buddhist traditions are generally vegetarian, interpreting this rule to apply to the eating of killed animals, while most Theravada Buddhist traditions are not vegetarian, interpreting the precept to mean that as long as a Buddhist practitioner does not do the killing him or herself, partaking of meat is alright.
The other precepts also have varying interpretations. Is sex outside of marriage 'sexual misconduct'? Are lies told to protect an innocent 'false speech?' Is a glass of wine an 'intoxicating substance that causes heedlessness?' As in all religions, Buddhist teachers throughout the centuries have debated these ethics, and come to varying conclusions. Many contemporary teachers have developed their own versions of the precepts, more applicable to modern life. Vietnamese Zen monk, teacher and author Thich Nhat Hanh has developed 'Five Mindfulness Trainings', that elaborate more on each precept. His Third Mindfulness Training, for example, is called 'Loving Speech and Deep Listening':
"Aware of the suffering caused by unmindful speech and the inability to listen to others, I am committed to cultivating loving speech and compassionate listening in order to relieve suffering and to promote reconciliation and peace in myself and among other people, ethnic and religious groups, and nations. Knowing that words can create happiness or suffering, I am committed to speaking truthfully using words that inspire confidence, joy, and hope. When anger is manifesting in me, I am determined not to speak. I will practice mindful breathing and walking in order to recognize and to look deeply into my anger. I know that the roots of anger can be found in my wrong perceptions and lack of understanding of the suffering in myself and in the other person. I will speak and listen in a way that can help myself and the other person to transform suffering and see the way out of difficult situations. I am determined not to spread news that I do not know to be certain and not to utter words that can cause division or discord. I will practice Right Diligence to nourish my capacity for understanding, love, joy, and inclusiveness, and gradually transform anger, violence, and fear that lie deep in my consciousness."
(all five available in his book The Heart of the Buddha's Teaching)
Because they are centered on ethics, the Buddhist Precepts are sometimes compared to the 10 commandments in the Abrahamic religions (Judaism, Christianity, Islam.) However, the Precepts differ because they are training guidelines, not commandments. They are guidelines for personal spiritual practice, to aid one in achieving enlightenment/nirvana. In and of themselves, adherence to the Precepts does not guarantee enlightenment; they need to be viewed in the context of the entire Noble Eightfold Path.
Although it varies slightly in different schools of Buddhism, in general there is also a set of Eight Precepts and Ten Precepts. The Eight Precepts are often undertaken by lay men and women who would like to practice more intensely, or who are on retreat. The Eight Precepts includes the core Five Precepts plus:
6. I undertake to abstain from eating at the wrong time (the right time is after sunrise, before noon).
7. I undertake to abstain from singing, dancing, playing music, and attending entertainment performances.
8. I undertake to abstain from luxurious places for sitting or sleeping, and overindulging in sleep.
The Ten Precepts are for monastic practitioners. They include the prior Eight, although the third is more strict, vowing celibacy. The additional two Precepts are:
9. I undertake to abstain from wearing perfume, and using cosmetics and garlands (decorative accessories).
10. I undertake to refrain from taking money.
Many monastic traditions have dozens, or even hundreds, more Precepts detailing every aspect of monastic life.