Who are common men? Women class, as a class; and Śūdra, laborer class, working class; and strī-śūdra-dvijabandhūnaṁ, and dvija means twice-born, the higher caste. The higher caste means they must be twice-born. How is that? One birth is father and mother, real father and mother, and the next birth is spiritual master and the Vedas. That means when one is trained up in the matter of real knowledge—Veda means real knowledge—by the guidance of the spiritual master, he is supposed to be twice-born.
So dvija-bandhu. Twice-born means cultural society. Those who have Vedic cultured, those who have followed the Vedic principles rigidly, it doesn't matter whether he is a householder or a brahmacārī or a sannyāsī. There are eight divisions of human society: four divisions social structure, and four divisions for spiritual enlightenment. So unless the eight divisions are properly managed, that is not human society. Human society is distinct from animal society by culture. What is that culture? Vedic culture, knowledge. Vedic means knowledge. One must be equipped with full knowledge.