Sri Ishopanishad: Mantra 2
This second mantra of the yogic scripture Sri Ishopanishad refers to karma yoga, or devotional service.
A person may desire to live for hundreds of years if he works according to this truth because that sort of work will not bind him to the law of karma. And there is no alternative to this way for man.
~Sri Ishopanishad, Mantra Two
Everyone is engaged in action. The law of karma means that there are reactions to every action and that a person must endure the reactions to his actions.
According to yoga, every action, good or bad, produces some karmic reaction. Actions that are “bad” create bad karmic reactions. A person who engages in heinous criminal actions or who lives simply like an animal, exploiting others, will have to eat the bitter fruit of such actions in the future.