When bhakti was once accepted as a part of Indian religion, it was erected into a principle, analogous or superior to knowledge and was defined in Sûtras[432] similar to those of the Sâṅkhya and Vedânta. But its importance in philosophy is small, whereas its power as an impulse in popular religion has been enormous. To estimate its moral and intellectual value is difficult, for like so much in Hinduism it offers the sharpest contrasts. Its obvious manifestations may seem to be acts of devotion which cannot be commended ethically and belief in puerile stories: yet we find that this offensive trash continually turns into gems of religious thought unsurpassed in the annals of Buddhism and Christianity. The doctrine of bhakti is common to both Vishnuites and Śivaites. It is perhaps in general estimation associated with the former more than with the latter, but this is because the Bhagavad-gîtâ and various forms of devotion to Kṛishṇa are well known, whereas the Tamil literature of Dravidian Śivaism is ignored by many European scholars. One might be inclined to suppose that the emotional faith sprang up first in the worship of Vishṇu, for the milder god seems a natural object for love, whereas Śiva has to undergo a certain transformation before he can evoke such feelings. But there is no evidence that this is the historical development of the bhakti sentiment, and if the Bhagavad-gîtâ is emphatic in enjoining the worship of Kṛishṇa only, the Śvetâśvatara and Maitrâyanîya Upanishads favour Śiva, and he is abundantly extolled in many parts of the Mahâbhârata. Here, as so often, exact chronology fails us in the early history of these sects, but it is clear that the practice of worshipping Śiva and Vishṇu, as being each by himself all-sufficient, cannot have begun much later than the Christian era and may have begun considerably earlier, even though people did not call themselves Śaivas or Vaishṇavas.