Srimad Bhagavatham : 5.3.13.
Dear Lord, here is the great King Nabhi, whose ultimate goal in life is to have a son like You. Your Lordship, his position is like that of a person approaching a very rich man and begging for a little grain. Maharaja Nabhi is so desirous of having a son that he is worshiping You for a son, although You can offer him any exalted position, including elevation to the heavenly planets or liberation back to Godhead.
The priests were a little ashamed that King Nabhi was performing a great sacrifice just to ask the Lord’s benediction for a son. The Lord could offer him promotion to the heavenly planets or the Vaikuntam. Sri Caitanya Mahaprabhu has taught us how to approach the Supreme Lord and ask Him for the ultimate benediction. He said: na dhanam na janam na sundarim kavitam va jagad-isa kamaye. He did not want to ask the Supreme Lord for anything material. Material opulence means riches, a nice family, a good wife and many followers, but an intelligent devotee doesn’t ask the Supreme Lord for anything material. His only prayer is: mama janmani janmanisvare bhavatad bhaktir ahaituki tvayi. He wants to be engaged perpetually in the loving service of the Lord. He does not want promotion to the heavenly planets or mukti, liberation from material bondage. If this were the case, Sri Caitanya Mahaprabhu would not have said, mama janmani janmani. It doesn’t matter to a devotee whether or not he takes birth life after life, as long as he remains a devotee. Actually eternal liberty means returning home, back to Godhead. A devotee is never concerned about anything material. Although Nabhi Maharaja wanted a son like Vishnu, wanting a son like God is also a form of sense gratification. A pure devotee wants only to engage in the Lord’s loving service.