Srimad Bhagavatham : 5.5.6.
When the living entity is covered by the mode of ignorance, he does not understand the individual living being and the supreme living being, and his mind is subjugated to fruitive activity. Therefore, until one has love for Lord Vasudeva, who is none other than Myself, he is certainly not delivered from having to accept a material body again and again.
When the mind is polluted by fruitive activity, the living entity wants to be elevated from one material position to another. Generally everyone is involved in working hard day and night to improve his economic condition. Even when one understands the Vedic rituals, he becomes interested in promotion to heavenly planets, not knowing that one’s real interest lies in returning home, back to Godhead. By acting on the platform of fruitive activity, one wanders throughout the universe in different species and forms. Unless he comes in contact with a devotee of the Lord, a guru, he does not become attached to the service of Lord Vasudeva. Knowledge of Vasudeva requires many births to understand.
As confirmed in Bhagavad-gita (7.19):
"vasudeva sarvam iti sa mahatma sudurlabhah."
After struggling for existence for many births one may take shelter at the lotus feet of Vasudeva, Krishna. When this happens. one actually becomes wise and surrenders unto Him. That is the only way to stop the repetition of birth and death.
The living entity wanders throughout different planets in different forms and bodies, but if by chance he comes in contact with a bona fide spiritual master, by the grace of the spiritual master he receives Lord Krishna’s shelter, and his devotional life begins.