Shree Bhagavaan uvaacha:
trividhaa bhavati shraddhaa dehinaam saa svabhaavajaa |
saatvikee raajasee chaiva taamasee cheti taam shrunu || 2 ||

Shree Bhagavaan said:
Threefold is the faith that comes from the nature of the embodied ones, saatvic, raajasic and taamasic. Listen about that from me.

trividhaa : three fold
bhavati : is
shraddhaa : faith
dehinaam : embodied ones
saa : they
svabhaavajaa : come from nature
saatvikee : saatvic
raajasee : raajasic
cha : and
eva : also
taamasee : taamasic
cha : and
iti : in this manner
taam : about that
shrunu : listen
Arjuna began this chapter by posing the following question. If one does not have access to the scriptures but uses their faith to guide their lives, what kind of a position is that? Shri Krishna does not answer that question directly. The entire chapter, in fact, is the answer to that question.
It is not an easy question to answer because faith differs from person to person. We can say that we trust our faith, our conscience, to guide us towards performing right actions. But the faith of a terrorist is different than faith of a saint. If we do not have guru to guide us, we cannot assess our faith objectively. So how should we tackle this issue?
Shri Krishna gives us a starting point to help us. We first need to understand what he means when he says that faith comes from svabhaava or nature. What exactly is meant by nature here? Nature refers to the collection of samskaaraas or impressions that are present in a person, a “dehin” or embodied one, from birth until death. Whenever we perform an action and get its result, both the action and result are ingrained in our mind in the form of an impression. This impression is called as samskaara. Whenever we repeat the action and get the same result, the impression is further ingrained and strengthened. If we repeat it often enough, it becomes a habit. It could be a good habit such as respecting our elders, or a bad habit such as smoking.
So this nature, this collection of samskaaraas or impressions, is where our faith comes from. Now let’s go back to Arjuna’s question. In the absence of scriptures, in the absence of a rational, logical means to check our actions, what will happen if we use our faith instead? If someone swears loudly at us in the middle of the street, we will respond instinctively at that point rather than using logic or reason. We may punch the person who yelled at us, or we may ignore him. It depends on the makeup of our nature.
Now, based on the makeup of our nature, we can classify our faith into three types: saatvic, raajasic and taamasic. But it is difficult to do so directly. We will have to infer the nature of faith through something else. Shri Krishna tells Arjuna to listen, since he will explain how to do this.