Actually, this human form of life is meant for researching this: athāto brahma jijñāsā. The Vedānta-sūtra says. This human form of life is meant for searching out about Brahman, or the spirit, Absolute Truth. So the yoga system means that brahma-jijñāsā, to search out the Brahman principle within this material body. Matter and spirit. So that searching out, as recommended in the Bhagavad-gītā by Kṛṣṇa Himself... And Arjuna said that "The system You are recommending, or the haṭha-yoga system, is not possible for me." But Kṛṣṇa assured him that Arjuna was the greatest of all yogis. He, I mean to say, pacified him by saying that "Don't bother because you are unable to practice haṭha-yoga system, you are not a yogi. You are the best yogi. You are the best yogi." Why? He gave this formula, that yoginām api sarveṣām: (BG 6.47) "Of all different types of yogis..." There are haṭha-yogī, jñāna-yogī, dhyāna-yogī, bhakti-yogī, many, karma-yogī. There are many yogis. But Kṛṣṇa said, "Of all the yogis, the one yogi who is constantly thinking of Me within himself..." Yoginām api sarveṣāṁ mad-gatenāntar-ātmanā. Mad-gata. Kṛṣṇa says mad-gata. Means "simply upon Me, Kṛṣṇa." Antar-ātmanā, "within the heart." Sa me yuktatamaḥ: "He is the first-class yogi."
Now who can think of Kṛṣṇa always within himself? That is also very easy to understand. If you love somebody, then you can think of him always within yourself. Otherwise it is not possible. If you love somebody, then naturally you'll think of him always. That is described in the Brahma-saṁhitā:
- premāñjana-cchurita-bhakti-vilocanena
- santaḥ sadaiva hṛdayeṣu vilokayanti
- yaṁ śyāmasundaram acintya-guṇa-svarūpaṁ
- govindam ādi-puruṣaṁ tam ahaṁ bhajāmi
- (Bs. 5.38)
Premāñjana-cchurita-bhakti-vilocanena. One who has developed love of God, or Kṛṣṇa... When I speak of Kṛṣṇa, you should understand "God." Premāñjana-cchurita-bhakti-vilocanena (Bs. 5.38). Another name of Kṛṣṇa is Śyāmasundara. He is blackish like the cloud, but very beautiful; therefore His name is Śyāmasundara.