Scriptures state that ‘the Supreme Lord who is birthless takes many births’ by way of explaining His incarnations. Krishna clarifies this truth in greater detail with reference to the mode of incarnation, the nature of the physical form He assumes, the cause of His birth, etc., in the fourth chapter of the Bhagavad Gita, said Sri Goda Venkateswara Sastrigal in a discourse.
This explanation occurs in the course of Krishna’s exposition of the Karma yoga that includes Jnana yoga in its scope. When Krishna points out that the knowledge of this yoga has existed since the time of Manu and that in fact He had taught this to Vivasvan, Arjuna wonders how this could be possible. Krishna then points out that the incarnations of the Supreme Brahman are unique and exemplify His omniscience, omnipresence and omnipotence. Out of His own free will He incarnates at opportune times and for specific purposes.
What is important is that there are many differences between His birth and that of ordinary beings. He states that He has no birth or death and He is ever existent. If He is born, it is due to His Sankalpa or divine power defined as Atma Maya. All other beings are born in accordance to each one’s individual karma. Karma is associated with Prakriti and the three Gunas and produces bondage in the Jivatmas. Pointing out that He has taken many births even as Arjuna has taken many in the course of time, the Lord states that He knows them all while Arjuna does not. The Lord is aware of everything while Arjuna’s knowledge is bound by limitations of human faculties. “Whenever there is a decline of dharma and an increase in adharma, then I choose to incarnate,” says the Lord to Arjuna.