The Buddha taught that because of karma, beings are bound to the ever-turning wheel of rebirth. Only when a person stops believing in the existence of a permanent and real self can he or she become free from karma.
• What is karma? • How is karma carried from moment to moment and lifetime to lifetime? • Should one try to convince a new Buddhist to accept the principles of karma and rebirth? • How central is the doctrine of karma to Buddhism? Is it possible to call oneself a Buddhist without believing in karma? • Does karma mean you don’t have to work to alleviate perceived injustice?
What is karma ?
Perhaps we could begin with the description of the Buddha’s enlightenment experience as given in various sutras in the Middle Length Discourses of the Buddha (Pali, Majjhima Nikaya). This gives a very concise statement of the early Buddha’s understanding of karma.
The Buddha’s enlightenment unfolded by way of what are called the Three Higher Knowledges.
The first of these is the Buddha’s knowledge of his past lives—recollecting his previous lives going back hundreds of thousands of eons.
The second is his knowledge of the death and rebirth of beings, which involves understanding how beings transmigrate according to their karma. Perhaps I could read a passage describing this from the Bhayabherava Sutta: