CC Madhya 22.18
kṛṣṇa-bhakti vinā tāhā dite nāre phala
“Without devotional service, all other methods for spiritual self-realization are weak and insignificant. Unless one comes to the devotional service of Lord Kṛṣṇa, jñāna and yoga cannot give the desired results.
In the Vedic scriptures, stress is sometimes given to fruitive activity, speculative knowledge and the mystic yoga system. Although people are inclined to practice these processes, they cannot attain the desired results without being touched by kṛṣṇa-bhakti, devotional service. In other words, the real desired result is to invoke dormant love for Kṛṣṇa. Śrīmad-Bhāgavatam (1.2.6) states:
ahaituky apratihatā yayātmā suprasīdati
“The supreme occupation [dharma] for all humanity is that by which men can attain to loving devotional service unto the transcendent Lord. Such devotional service must be unmotivated and uninterrupted to completely satisfy the self.” Karma, jñāna and yoga cannot actually awaken love of Godhead. One has to take to the Lord’s devotional service, and the more one is inclined to devotional service, the more he loses interest in other so-called achievements. Dhruva Mahārāja went to practice mystic yoga to see the Lord personally, face to face, but when he developed an interest in devotional service, he saw that he was not being benefited by karma, jñāna and yoga.