When we speak of Indian ethics, its early beginnings have to be traced from the Vedas, particularly the Rig Veda. One of the central ethical concepts of the Rig
Veda is ‘rta’, a conception of unifying order or moral law, pervading all things.
The concept ‘rta’ has given rise to two other important concepts, the concept of Dharma and the concept of Karma. The concept Dharma has got so different and divergent meanings, but generally it is known as duty.The concept Karma signifies that there is a uniform moral law, governing the actions of man and the rewards and the punishments appropriate to their actions. ‘Rta’ is the foundation of these two concepts.
The more important and essential element in the Vedic ethics is that of love and worship offered to the gods in complete submission. Moral order or law is reflected in the right performance of sacrifices and so one who performs these sacrifices and the ceremonial duties laid down in the scriptures, would achieve the goal of eternal happiness in heaven. So the ethics of the Vedic Hindus is primarily a god-oriented ethics.
The highest goal of life for the Upanishads is no longer happiness as in the Rig Veda, but liberation from bondage to the transitory existence and the re-attainment of the inner essence of the soul. The Upanishadic ethics is primarily atmancentric and intellectualistic.
The Upanishads declare that the Vedic sacrifices are totally irrelevant for the realization of moksha. And so man is constantly exhorted to seek his individual liberation and not worry about other social, moral obligation.This kind of philosophical individualism definitely undermines the values of social morality.
For the Upanishads, the identification and the realization of the self with Brahman is very important. In this metaphysical realm only we can speak of Upanishadic ethics. The oldest Upanishads say that the perfect sage is a saint who burns evil away and he is free from evil. So it is in the avoidance of evil, we can see the clear moral teaching in the Upanishads.
Katha Upanishad declares that he who is always impure is born again and again that he fails to reach the highest goal. Good conduct is very much necessary for the attainment of man’s metaphysical good (identification of the self with Brahman). And man who is wise is morally a good man whose nature approximates to the divine model .
So the Upanishads are clear in saying that the man who has wisdom does not sin. He ceases to do evil and through his wisdom he annuls the evil of his former life.