In Geetaa, 4-8, Bhagavaan Krishn says - "For the protection of those who are committed to Dharm, for the destruction (conversion) of those who follow A-Dharm, and for the establishment of Dharm, I come into being in every age. This dharma is two-fold: Karm (action) and Gyaan (knowledge). It is said, "The entire Ved is the source of Dharm (righteous conduct)."

That Dharm is two fold: righteous activity and withdrawal from it by knowledge. The body of knowledge called Ved is the repository of Dharm. The Ved is broadly divided into two sections. The first section is Karm Kaand, which teaches activity-based Dharm. It is also called Pravritti Dharm. The second portion of the Ved teaches a totally different kind of Dharm, called Aatm Dharm. It is also called Nivritti Dharm (withdrawal from activity by the knowledge that Aatmaa is not the agent of actions). Strategic advance into the world is Dharm; so also deliberate withdrawal from the world is Dharm. On the eleventh day of the lunar cycle, namely, on Ekaadashee day, fasting is Dharm, while on the next day, that is Dwaadashee, taking food early in the morning is Dharm

Dharm is normally taken care of by the society. However, when Dharm declines in the society and A-Dharm increases, corrective measures have to be taken. In such a situation Bhagavaan comes forth and corrects the imbalance. Correction of the imbalance is also two-fold. In case of Pravritti Dharm, Bhagavaan comes in the form of Avataar, an incarnation, and He punishes the wicked and rewards the virtuous. That is what, for example, Lord Raam did and we have quite a few such Avataar like Matsya, Koorm etc. Aatm Dharm also declines over a period of time.

Dharm can never be destroyed. It only disappears temporarily. Some people claim that Sanskrit is a dead language. This is not correct. The fact is that the language is not in common use now-a-days. But even that situation is quickly changing and once again Sanskrit is becoming popular. In the same way, this Aatm Dharm also declines in certain times. On such occasions, Bhagavaan appears in a suitable incarnation and makes it prominent through his teachings. The Lord appeared in the incarnation of Krishn and took care of Pravritti Dharm by killing the wicked persons like Kans and by teaching Geetaa to Arjun. This is why Krishna is called Jagad-Guru - the teacher for the entire humanity. There is an interesting difference between the incarnations of Raam and Krishn. The sage Vashishth teaches Raam: Tat Twam Asi, that (the supreme reality) art thou; but Krishn often proclaims himself thus: Aham Brahmasmi, I am the Supreme reality of this universe.

Certain Avataar like Raam are meant to protect the Pravritti Dharm exclusively. Certain others like Krishn Avataar protected both Pravritti as well as Nivritti Dharm. The incarnation of the Lord as Dakshinaamoorti is meant for safeguarding Aatm Dharm exclusively. This Avataar of the Lord is described in the Soot Sanhitaa of the Skand Puraan. The Skand Puraan is a voluminous treatise, almost as big as the Mahaabhaarat (100,000 verses).