Faith provides the significance and impulsion of our spiritual seeking, but the mind and its powers provide the practical implementation of faith in our existence. Sri Aurobindo explains the different roles: “Faith, sraddha, the will to believe and to be, know, live and enact the Truth that we have seen is the principal factor, the indispensable force behind a self-developing action, most of all behind the growth of the soul by works into its full spiritual stature. But there are also the mental powers, the instruments and the conditions which help to constitute the momentum, direction and character of the activity and are therefore of importance for a full understanding of this psychological discipline.”
The Gita, having first explored the nature of faith and its importance, next turns its attention to the instruments, the mental powers. The three Gunas of Nature impact the mental powers as well, and it is the exact balance and application of these “Guna-conditioned” mental forces, implementing the essential faith of the soul (also formed and conditioned by the balance of the three Gunas within each individual), that brings about the wide variety of different results we can observe around us, as well as the wide variety of focus and methodology that has led to countless numbers of principles, religions, philosophies and creeds throughout humanity’s existence.
The Gita has systematically been addressing the questions, issues and principles, leading up to its ultimate statement, and the time it spends reviewing the impact of the Gunas indicates the importance and value of understanding their interaction.
Sri Aurobindo, Essays on the Gita, Second Series, Part II, Chapter 19, The Gunas, Mind and Works, pg. 476