God’s incarnations serve many purposes. He alone is capable of establishing Dharma when evil dominates the good. Time and again, He has descended to this world to fulfil this mighty task.
The Bhagavata Purana describes His Avatars to explain their impact in this regard and also of the ways in which people are motivated to worship Him and remain devoted to Him. He reinforces His law and advises people to abide by it and seek salvation.
A Jivatma’s birth happens according to one’s Karma. But the Lord’s birth is unique and not bound by anyone or anything, though He readily acquiesces to the wishes of His devotees, as was the case when he was born as Kapila in Kardama’s household, said Sri V. S. Karunakarachariar in a lecture.
Kardama is overwhelmed by the Lord’s compassion as He had chosen to be born to fulfil his wishes. The sage then surrenders to the Lord who releases him from worldly ties and blesses him to spend the rest of his time in meditation.
Kapila then imparts the truths of life and immortality to His mother, Devahuti, who is also very devout.
The crux of the message is to understand the nature of the Self (Atma). Before every birth the Jivatma is aware of his past life. But this awareness is lost when he enters this material world. Succumbing to the pulls of this world of senses, he loses his moorings and this cycle continues endlessly. Attachment to sense objects is the prime cause of bondage. The Jivatma’s affiliation with the three Gunas born of Prakriti binds him to the cycle of birth. Man's fears arise from the ephemeral quality of life. This fear is overcome when one identifies with the immortal Self.
The only way out is to seek salvation and this is possible by cultivating detachment to worldly objects and by remaining devoted to the service of God. Such an attitude and way of life is gained through association with the pious. Hearing of the Lord’s greatness and singing His praises at all times are beneficial activities that purify the mind. There is nothing to fear for one who understands the supremacy of God and willingly serves Him at all times.