Prabhupāda Says: The Vaiṣṇavas are by far the greatest philosophers in the world, and the greatest among them was Śrīla Jīva Gosvāmī Prabhu, whose philosophy was again presented less than four hundred years later by Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura Mahārāja. Therefore one must know very well that Vaiṣṇava philosophers are not sentimentalists or cheap devotees like the sahajiyās. All the Vaiṣṇava ācāryas were vastly learned scholars who understood Vedānta philosophy fully, for unless one knows Vedānta philosophy he cannot be an ācārya. To be accepted as an ācārya among Indian transcendentalists who follow the Vedic principles, one must become a vastly learned scholar in Vedānta philosophy, either by studying it or hearing it.
Bhakti develops in pursuance of Vedānta philosophy. This is stated in Śrīmad-Bhāgavatam (1.2.12):
tac chraddadhānā munayo jñāna-vairāgya-yuktayā
paśyanty ātmani cātmānaṁ bhaktyā śruta-gṛhītayā
The words bhaktyā śruta-gṛhītayā in this verse are very important, for they indicate that bhakti must be based upon the philosophy of the Upaniṣads and Vedānta-sūtra. Śrīla Rūpa Gosvāmī said:
aikāntikī harer bhaktir utpātāyaiva kalpate
“Devotional service performed without reference to the Vedas, Purāṇas, Pañcarātras, etc., must be considered sentimentalism, and it causes nothing but disturbance to society.” There are different grades of Vaiṣṇavas (kaniṣṭha-adhikārī, madhyama-adhikārī and uttama-adhikārī), but to be a madhyama-adhikārī preacher one must be a learned scholar in the Vedānta-sūtra and other Vedic literatures because when bhakti-yoga develops on the basis of Vedānta philosophy it is factual and steady. In this connection we may quote the translation and purport of the verse mentioned above
We are so blessed to be given this most sublime philosophical treatise by the most exalted Vaiṣṇava Brāhmaṇa His Divine Grace AC Bhaktivedanta Swami Prabhupāda. How can we not but dive into the nectar of this most glorious literature and allow it to consume us completely?
We as a Vaiṣṇava society have no need to syncretize or homogenize or hybridize our philosophy with any man made Academic concoction and procedure or lesser religious thought. We stand alone undefeatable in the simplicity and complexity of the most ancient philosophical study given by the Lord Himself, Śrī Kṛṣṇa.
All we have to do is study our own teachings given by His Divine Grace AC Bhaktivedanta Swami Prabhupāda and continually make ourselves known to the greater human society as rational intelligent people who understand the nature of material existence and have something valid, tangible and sublime to offer them.
All glories to His Divine Grace AC Bhaktivedanta Swami Prabhupāda!