śabdādīn viṣayān anya
The members of the four divisions of human life, namely the brahmacārī, the gṛhastha, the vānaprastha and the sannyāsī, are all meant to become perfect yogīs or transcendentalists. Since human life is not meant for our enjoying sense gratiﬁcation like the animals, the four orders of human life are so arranged that one may become perfect in spiritual life. The brahmacārīs, or students under the care of a bona ﬁde spiritual master, control the mind by abstaining from sense gratiﬁcation. A brahmacārī hears only words concerning Kṛṣṇa consciousness; hearing is the basic principle for understanding, and therefore the pure brahmacārī engages fully in harer nāmānukīrtanam – chanting and hearing the glories of the Lord. He restrains himself from the vibrations of material sounds, and his hearing is engaged in the transcendental sound vibration of Hare Kṛṣṇa, Hare Kṛṣṇa. Similarly, the householders, who have some license for sense gratiﬁcation, perform such acts with great restraint. Sex life, intoxication and meat-eating are general tendencies of human society, but a regulated householder does not indulge in unrestricted sex life and other sense gratiﬁcation. Marriage on the principles of religious life is therefore current in all civilized human society because that is the way for restricted sex life. This restricted, unattached sex life is also a kind of yajña because the restricted householder sacriﬁces his general tendency toward sense gratiﬁcation for higher, transcendental life.