Action, which springs from the mind, from speech, and from the body, produces either good or evil results; by action are caused the conditions of men, the highest, the middling, and the lowest. A man obtains the result of a good or evil mental act in his mind; that of a verbal act in his speech; that of a bodily act in his body. In consequence of sinful acts committed with his body, a man becomes in the next birth an inanimate thing; in consequence of sins committed by speech, he becomes a bird or a beast; in consequence of mental sins he is reborn in a low caste.

(The Law of Manu)