Even though the training in ethics takes many forms, the ethics of abandoning the ten non-virtues is their basis. Of the ten non-virtues, three pertain to bodily actions, four to verbal actions, and three to mental actions.
The three mental non-virtues are: Covetousness: thinking, "May this become mine," desiring something that belongs to another. Harmful intent: wishing to injure others, be it great or small injury. Wrong view: viewing some existent thing, such as rebirth, cause and effect, or the Three Jewels*, as non-existent. The opposite of these ten non-virtues are the ten virtues, and engaging in them is called the practice of ethics.
*The core of Buddhism: Buddha, his doctrine (Dharma), and the Spiritual Community.