BG Chap 10 - Understanding buddhi yoga
In the Second Chapter the Lord, instructing Arjuna, said that He had spoken to him of many things and that He would instruct him in the way of buddhi-yoga. Now buddhi-yoga is explained here in the tenth chapter. Buddhi-yoga itself is action in Kṛṣṇa consciousness; that is the highest intelligence. Buddhi means intelligence, and yoga means mystic activities or mystic elevation. When one tries to go back home, back to Godhead, and takes fully to Kṛṣṇa consciousness in devotional service, his action is called buddhi yoga. In other words, buddhi-yoga is the process by which one gets out of the entanglement of this material world. The ultimate goal of progress is Kṛṣṇa. When a person knows the goal of life but is addicted to the fruits of activities, he is acting in karma-yoga. When he knows that the goal is Kṛṣṇa but he takes pleasure in mental speculations to understand Kṛṣṇa, he is acting in jñāna-yoga. And when he knows the goal and seeks Kṛṣṇa completely in Kṛṣṇa consciousness and devotional service, he is acting in bhakti-yoga, or buddhi-yoga, which is the complete yoga. This complete yoga is the highest perfectional stage of life.