Desire and aversion occur naturally to a soul. Because of the conditioning of desire and aversion, karma clings to the soul.  After death,  this karmic bondage draws the soul into physical existence again where it builds a body based upon its karma.  Once in the body, individual acquires senses.   Through the senses, objects in the environment are perceived.  From   perception comes desire and aversion and the cycle begins again.  This cycle ends for those who  attain liberation, whereas it is unending for those who do not.   - Panchastikaya - sura


The principle or ethical law, originally developed in South Asian religions, that determines one's past, current, and future existences as well as commensurate rewards and punishments in accordance with thoughts and practices.   First appearing textually in the Upanishads (eighth-fifth centuries BC), the concept of karma is a fundamental presupposition of all South Asian religious systems, with the exception of the materialists, who deny its efficacy. Going beyond the Brahmana texts' view that karma refers to ritual activity, the Upanishads imply that karma refers to all types of action as well as to a more abstract principle or system of norms pertaining to action and consequences. Brihadaranyaka Upanishad (3.2.13) states the common view that one becomes good by good action and evil by evil action. The same Upanishad (4.4.5) also says that karma is rooted in kama ("desire").


The concept of karma, however, may predate its appearance in Vedic texts and originate in traditions indigenous to the Indian subcontinent. Jainism, which maintains the view that karma is a substance from which one must ultimately extricate oneself, may present a more archaic notion than that of the Upanishads.


 Across South Asian religions, the notion of karma implies an utterly consistent and impersonal process of cause and effect that can be used to describe, explain, or predict the past, present, and future condition of things. In later Hindu texts karma is treated as yet another creation of the deity. In the Bhagavad Gita, for example, the avatar Krishna restates Upanishadic views about its independent role in determining causal material processes and asserts his own divine prerogative to transcend its effects.  


Interpretation of the process of karma and its implications has preoccupied South Asian religious, social, and medical traditions. All agree that current situations are partially predetermined by the fruit (phala), good or bad, of past sown seeds (bija) and that continuing and future effects will be determined by the ongoing accumulation of deeds and intentions. Hindus, Buddhists, Jains, and others all assume karma to be essential to understanding an individual's current life situation and future prospects, as well as his or her moral destiny, suffering, good fortune, and social status. However, differences arise as to the nature of actions, results, and the relationship of the two. All use karma to explain descriptive and normative realities and all consider it a factor in understanding the achievement of ultimate freedom from suffering and rebirth.  


While happiness in present and future lives depends on building a store of good merit through conscientious actions or karma, most would concur that no amount of accumulated good deeds is ever sufficient to achieve the highest human goal, that of bringing the cycle of death and rebirth, itself generated and sustained by karma, to an end. Rather, one must reach a point at which one seeks a means by which to free oneself from karma and engage in a discipline, such as the various yogas involving action, knowledge, devotion, and grace, whereby one is no longer subject to either its processes or results.


  The ‘soul’ continues on through cycles of life and death. The effect of the "karma’ from past lives is seen in the genetic inheritance and the environment into which the individual enters life. It is from these first roots that the entire life is built. This is the effect of karma from one life to another.   Though memories of our past lives will affect us. we do not consciously recall them because those memories do not reside in our new temporary body, but dwell more permanently in the ‘soul’. 


How is karma revealed?. It  is manifested in each individual through character, tendencies, talents, interests and abilities, the qualities of the physical body and the environment into which one is born and all subsequent environments..   Karma is expressed as the genes we are born with and the environment we are born into.  Everything else in our life can be traced back to those factors.   Those factors are determined by our karma - the package of desire and aversion we had at our last death.