Prabhupada's lecture - Śrīmad-Bhāgavatam 1.8.34 - Bombay, October 14, 1974
So this big, big lump of matter, earthly planet, they are actually not heavy, but it becomes heavier when there are demons. Demons means material activities. If there is spiritual activity, it remains very light. And if there is too much material activity and materialistic persons, it become heavier and troublesome. So such time became possible, and therefore the earthly planet went to Brahmā to appeal to Viṣṇu to take His incarnation. So somebody says that bhārāvatāra..., tāraṇāya, avatāraṇāya, to diminish the burden, burden... Just like a bad son is a burden of the father. This has been explained by Cāṇakya Paṇḍita that a stupid son... Ko 'rthaḥ putreṇa jātena yo na vidvān na bhaktimān: "What is the use of getting a son who is neither learned nor a devotee? Useless." Ko 'rthaḥ putreṇa jātena: "Such kind of son, what is the use?" The son who is not a devotee... Two things are required: the son should be a devotee or a learned.
Without being learned, nobody can become devotee. If one becomes devotee, he's learned also. But sometimes materially learned, not devotee, it happens. So if one is neither learned nor devotee, what is the use of such son? The example is given: kāṇena cakṣuṣā kiṁvā cakṣuḥ pīḍaiva kevalam: "If you have got one eye, cataract, you cannot see, but it is always troublesome." Unless you get it operated, it is simply troublesome. In many places it is said, Cāṇakya Paṇḍita... Ko 'rthaḥ putreṇa jātena. Varam eko guṇī putro na ca mūrkha-śatair api: "If you get one son, very qualified, that is preferred. What is the use of having many sons and all of them are rascals and fools?" Na ca mūrkha-śatair api.