Nārada's definitions give us portraits of complete dedication, of love, and of oneness of interest between the Supreme Lord and His devotee. When we read a superb sūtra such as number 49 or 67 we may think, "Now he has given the last word on bhakti: nothing more can be said as briefly and as well." But then Nārada delights us with even more precise aphorisms on bhakti-yoga.
This sūtra is quite similar to number 41: "The Lord and His pure devotees are nondifferent." In the Gurv-aṣṭaka, Śrīla Viśvanātha Cakravartī Ṭhākura states, "The spiritual master is to be honored as much as the Supreme Lord because he is the most confidential servitor of the Lord. This is acknowledged in all revealed scriptures and followed by all authorities." Although a qualified student of bhakti knows that the Vaiṣṇava is not God Himself, the disciple experiences Kṛṣṇa's direct presence in the form of His dedicated servant. And the disciple is fully satisfied in serving the Supreme Lord by serving His pure devotee, who is the transparent medium to Kṛṣṇa.
When Sanātana Gosvāmī met Lord Caitanya, the Lord told him, "Lord Kṣṇa has saved you from life's deepest hell." Sanātana replied, "I do not know who Kṛṣṇa is. As far as I am concerned, I have been released from prison only by Your mercy" (Cc. Madhya 20.64). The disciple's gratitude toward the Vaiṣṇava is also expressed in Bhaktivinoda Ṭhākura's song Ohe! vaiṣṇava ṭhākura: "Kṛṣṇa is yours. You're able to give Him to me, for such is your power. I am indeed wretched and simply run after you, crying, 'Kṛṣṇa! Kṛṣṇa!' "
This is why the place where great devotees reside is a tīrtha and why Nārada says that they purify established holy places and give authority to the scriptures—because they are tan-mayāḥ, "filled with Him."