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.
That austerity which is undertaken with a foolish intent, by causing pain to oneself, or for the destruction of others-that is said to be born of tamas.OPEN VERSE
That gift is referred to as born of sattva which gift is given with the idea that it ought to be given, to one who will not serve in return, and at the (proper) place, (proper) time and to a (proper) person.OPEN VERSE
But the gift which is given expecting reciprocation, or again, with a desire for its result, and which is given grudgingly, - that is considered to be born of rajas.OPEN VERSE
The gift which is made at an improper place and time, and to undeserving persons, without proper treatment and with disdain, is declared to be born of tamas.OPEN VERSE
'Om-tat-sat' ['Om, That, Existence': 'Om iti brahma, Om is Brahman'; 'Tattvamasi, Thou art That'; and 'Sadeva somya idamagra asit, This was Existence alone in the beginning, O amiable one'-in these texts Brahman is indicated by the words Om, tat, sat.]-this is considered to be the threefold designation of Brahman. The Brahmanas and Vedas and the sacrifices were ordained by that in the days of yore.OPEN VERSE
Therefore, acts of sacrifice, charity and austerity as prescribed through injunctions, of those who study and expound the Vedas, always commence after uttering the syllable Om.OPEN VERSE