The Brahmana thought that there were three kinds of duties laid down for observances. There were, first, the duties ordained in the Vedas about the order in which he was born and the mode of life he was leading. There were, secondly, the duties sanctioned in the scriptures, viz., those especially called the Dharmashastras. And, thirdly, there were those duties that eminent and revered men of ancient times have followed, through not laid down either in the Vedas or the Scriptures.
ततः स धर्मं वेदोक्तं तथा शास्त्रोक्तमेव चा शिष्टाचीर्णं च धर्मं च त्रिविधं चिन्त्य चेतसा॥