The seventeenth chapter of the Bhagavad Gita is Sraddhatraya Vibhaga Yoga. In this chapter, Krishna describes the three types of faith corresponding to the three modes of the material nature. Lord Krishna further reveals that it is the nature of faith that determines the quality of life and the character of living entities. Those who have faith in passion and ignorance perform actions that yield temporary, material results while those who have faith in goodness perform actions in accordance with scriptural instructions and hence their hearts get further purified.
They declare that sacrifice as 'done through tamas' which is contrary to injunction, in which food is not distributed, in which mantras are not used, in which offerings are not made to priests, and which is devoid of faith.OPEN VERSE
The worship of gods, twice-born, venerable persons and the wise; purity, straightforwardness, celibacy and non-injury, -are said to be bodily austerity.OPEN VERSE
That speech which causes no pain, which is true, agreeable and beneficial; as well as the practice of study of the scriptures, -is said to be austerity of speech.OPEN VERSE
Tranquillity of mind, gentleness, reticence, withdrawal of the mind, purity of heart, -these are what is called mental austerity.OPEN VERSE
When that threefold austerity is undertaken with supreme faith by people who do not hanker after results and are self-controlled, they speak of it as born of sattva.OPEN VERSE
That austerity which is undertaken for earning a name, being honoured and worshipped, and also ostentatiously, -that is spoken of as born of rajas, belonging to this world, uncertain and transitory.OPEN VERSE