Bhakti or love of God is a very ancient religious sentiment. Its origin can be traced even to the Ṛgveda (1.156.3; 8.98.11). It appears like a flash of lightning in the Upaniṣads (vide Kaṭha Upaniṣad 2.23; Śvetāśvatara Upaniṣad 6.23). By the time of the epics and the purāṇas it has grown to voluminous proportions.
Gradually bhakti was developed into a doctrine or a religion or even a philosophy. This has been christened as ‘Bhāgavata-dharma.’ The term ‘Bhāgavata-dharma’ has been derived from the word ‘Bhagavat’ or God, endowed with ‘bhaga’ or the six divine attributes of aiśvarya (lordship), dharma (righteousness), yaśas (celebrity), śrī (wealth and splendour), jñāna (knowledge) and vairāgya (detachment). Since this God is identified with Nārāyaṇa, this religion is also called ‘Nārāyaṇīya-dharma.’ It was also called ‘Sātvata-mata’ since it was current among the people of the ‘satvat’ tribe to which Kṛṣṇa belonged. As it teaches ekānta-bhakti or single-minded devotion, it has come to be known as ‘Ekāntika or Aikāntika mata.’ Other names of this system are: Pāñcarātra mata (religion as taught in the Pāñcarātra Āgamas) and Vaiṣṇava-dharma (religion of the followers of Viṣṇu).
The Nārāyaṇīya section of the Mahā-bhārata (Śāntiparva ch. 334 onwards), Viṣṇupurāṇa, Bhagavadgītā, Bhāgavata, Pāñcarātra Āgamas, Bhaktisūtras of Śāṇḍilya and Nārada—these are the sources of the Bhāgavata-dharma.
Not being satisfied with the impersonal Brahman of the Upaniṣads, the Bhāgavata religion has converted it into the Personal God. Īśvara, Mahāviṣṇu, Nārāyaṇa and Kṛṣṇa-Vāsudeva are some of the names most commonly used with respect of him. He cannot be apprehended by the senses nor by logic. Śrutis or scriptures, at best, point towards him. His grace is the supreme factor in realizing him. Ekānta-bhakti or single-minded devotion is the only mode by which his grace can be obtained and he can be apprehended. Though He is ‘sarvatantra-svatantra’ or supremely independent, actually it is not so! He is always ‘bhakta-parādhīna’ or subject to the will of the devotees! He is ever fond of those that are devoted to him and reveals himself to them. Prapatti or śaraṇāgati (complete resignation) is another means of attaining him.
The Caturvyūha doctrine is another speciality of this Bhāgavata-dharma. The four vyūhas or emanations of the Lord Viṣṇu are: Vāsudeva, Saṅkarṣaṇa, Pradyumna and Aniruddha. They are different aspects of manifestation of the six qualities known as ‘bhaga’ mentioned earlier. While Vāsudeva has all the six qualities in full measure, the other three have two each in greater measure than the others.
Followers of the Bhāgavata-dharma are called ‘bhāgavatas.’