This verse is the summation of the Seventh and Eighth Chapters, particularly as the chapters deal with Kṛṣṇa consciousness and devotional service. One has to study the Vedas under the guidance of the spiritual master and undergo many austerities and penances while living under his care. A brahmacārī has to live in the home of the spiritual master just like a servant, and he must beg alms from door to door and bring them to the spiritual master. He takes food only under the master's order, and if the master neglects to call the student for food that day, the student fasts. These are some of the Vedic principles for observing brahmacarya.
After the student studies the Vedas under the master for a period from five to twenty years, he may become a man of perfect character. Study of the Vedas is not meant for the recreation of armchair speculators, but for the formation of character. After this training, the brahmacārī is allowed to enter into household life and marry. When he is a householder, he also has to perform many sacrifices and strive for further enlightenment. Then after retiring from household life, upon accepting the order of vānaprastha, he undergoes severe penances, such as living in forests, dressing with tree bark, not shaving, etc. By carrying out the orders of brahmacārī, householder, vānaprastha and finally sannyāsa, one becomes elevated to the perfectional stage of life. Some are then elevated to the heavenly kingdoms, and when they become even more advanced they are liberated in the spiritual sky, either in the impersonal brahmajyoti or in the Vaikuṇṭha planets or Kṛṣṇaloka. This is the path outlined by Vedic literatures.
The beauty of Kṛṣṇa consciousness, however, is that by one stroke, by engaging in devotional service, one can surpass all rituals of the different orders of life.
One should try to understand the Seventh and Eighth Chapters of the Gītā not by scholarship or mental speculation, but by hearing them in association with pure devotees. Chapters Six through Twelve are the essence of the Gītā. If one is fortunate to understand the Gītā-especially these middle six chapters-in the association of devotees, then his life at once becomes glorified beyond all penances, sacrifices, charities, speculations, etc. One should hear the Gītā from the devotee because at the beginning of the Fourth Chapter it is stated that the Gīta can only be perfectly understood by devotees. Hearing the Gītā from devotees, not from mental speculators, is called faith. Through association of devotees, one is placed in devotional service, and by this service Kṛṣṇa's activities, form, pastimes, name, etc., become clear, and all misgivings are dispelled. Then once doubts are removed, the study of the Gītā becomes extremely pleasurable, and one develops a taste and feeling for Kṛṣṇa consciousness. In the advanced stage, one falls completely in love with Kṛṣṇa, and that is the beginning of the highest perfectional stage of life which prepares the devotee's transferral to Kṛṣṇa's abode in the spiritual sky, Goloka Vṛndāvana, where the devotee enters into eternal happiness.