The Gita proposes that life lived according to the normal impulsion of desire and personal gratification has no opportunity to break out of the fixed results of the bondage to the action of the Gunas, primarily, in this case Rajas and Tamas. It is a virtually universal experience of humanity that those who become aware of some larger meaning or purpose to life tend to develop and follow a series of precepts or guidelines that have, as one of the basic tenets, the submergence of the ego and its desires to a larger, higher or wider aim. To this end, we have seen a large array of religions, philosophies, creeds and beliefs, all of which set forth some definition or set of ethical concepts to be followed to allow the individual to free himself from the enslavement to the life of desire. These paths all share, not only this common aspiration, but also a basis in attempting to uplift and govern the raw force of Rajas or the darkness of Tamas with a principle that is founded on the application of the Guna of Sattwa.
The Gita suggests that the individual totally enslaved to passions, desires, or even simple pleasures satisfying to the ego, does not have a platform with which to lift himself into a new diviner sphere. The application of a more or less disinterested, wider rule or principle, representing the influence of Sattwa into the process, is the first step toward achieving the liberation being sought.
Sri Aurobindo describes the situation: “This greater rule the individual finds usually outside himself in some more or less fixed outcome of the experience and wisdom of the race, which he accepts, to which his mind and the leading parts of his being give their assent or sanction and which he tries to make his own by living it in his mind, will and action.”
It is this standard which the Gita calls the faith held by the individual. Faith is not solely limited to a religious context. Whether it is a religion, a philosophy, an ethical standard, a moral law, or simply a developed belief, “…in proportion as I have a sincerity and completeness of faith in it and an intensity of will to live according to that faith, I can become what it proposes to me, I can shape myself into an image of that right or an exemplar of that perfection.”
Sri Aurobindo, Essays on the Gita, Second Series, Part II, Chapter 18, The Gunas, Faith and Works, pp. 461-462