According to Vedic civilization, therefore, a child—he may be a king's son or a poor man's son—must go to gurukula and live for some time under the training of the spiritual master to be very thickly connected with Nārāyaṇa and Kṛṣṇa. The āśrama . . . just like we have got this Kṛṣṇa conscious āśrama, there is rules and regulation that one should rise early in the morning, chant Hare Kṛṣṇa mantra, and so many duties are there. They are all in connection with Kṛṣṇa.
So if a child is trained up in that way, then he becomes automatically Kṛṣṇa conscious. And if a child becomes Kṛṣṇa conscious up to the age of twenty, twenty-five years, then naturally he becomes a devotee of Kṛṣṇa. So when he enters his family life, although he accepts wife and children, he cannot forget Kṛṣṇa. Therefore his household life also continues Kṛṣṇa conscious. Naturally, at the age of fifty he leaves the family connection and accepts the vānaprastha. And then, when he is fully trained, he accepts sannyāsa.
This is the system of varṇāśrama-dharma—four kinds of varṇas and four kinds of āśrama. It is very scientific. The whole idea of human civilization should be how to push one to Kṛṣṇa consciousness, to Viṣṇu. Because they do not know, na te viduḥ svārtha-gatiṁ hi viṣṇum (SB 7.5.31). The real interest is to approach Viṣṇu, to go back to home, go back to Godhead. That he does not know. He is entangled with these material affairs. Anartha. They are called anartha. They are not required.
When you get a human form of body you must know that your food and shelter is already ordained. You don't require to try for this. Even the birds and beasts, they do not try for their food and shelter. They are certain that, "Somewhere we have got our shelter and there is somewhere my food."