The fourth chapter of the Bhagavad Gita is Jnana Karma Sanyasa Yoga. In this chapter, Krishna glorifies the Karma Yoga and imparts the Transcendental Knowledge (the knowledge of the soul and the Ultimate Truth) to Arjuna. He reveals the reason behind his appearance in this material world. He reveals that even though he is eternal, he reincarnates time after time to re-establish dharma and peace on this Earth. His births and activities are eternal and are never contaminated by material flaws. Those persons who know and understand this Truth engage in his devotion with full faith and eventually attain Him. They do not have to take birth in this world again.
O scion of the Bharata dynasty, whenever righteousness is on the decline, unrighteousness is in the ascendant, then I body Myself forth.OPEN VERSE
For the protection of the pious, the destruction of the evil-doers, and establishing virtue, I manifest Myself in every age.OPEN VERSE
He who thus knows truly the divine birth and actions of Mine does not get re-birth after casting off the body. He attains Me, O Arjuna.OPEN VERSE
Many who were devoid of attachment, fear and anger, who were absorbed in Me, who had taken refuge in Me, and were purified by the austerity of Knowledge, have attained My state.OPEN VERSE
According to the manner in which they approach Me, I favour them in that very manner. O son of Partha, human beings follow My path in every way.OPEN VERSE