Bhakti yoga seeks salvation through the path of devotion to a personal representation of God. During the centuries that preceded Patanjali, India had been dominated by the atheistic or nontheistic philosophies of original Buddhism, Samkhya, Jainism, and the impersonal God of the Upanishads. The impulse to worship and serve a personal God (which a Christian would consider God-given) therefore had long been frustrated. Patanjali himself made a place for this, even though it was not a necessary part of his philosophical system. In chapter 1, verses 23-26 of the Yoga Sutras, he included the concept of Ishwara (or Ishvara), the personal God. Ishwara was not considered to be the creator God but was rather the supreme parusha, untouched by prakriti and the law of karma, who assists all parushas who are devoted to him in attaining moksha.
Like other concepts in Patanjali’s belief system, Ishwara survived the assimilation of yoga into the monistic Vedanta belief system, and he was now believed to be the personal manifestation of the impersonal Brahman. The dominance of Shankara’s unqualified monism created an acute longing in the hearts of many Hindus for a personal relationship with the divine, since God was believed to be impersonal and not separate from one’s true self. Ishwara helped fill that need, as did devotion to the various gods and goddesses of Hinduism and also to gurus, who were often believed to be divine; yet none of these gods were satisfying to those who wanted a personal relationship with Ultimate Reality Itself.
This need ultimately would be addressed by Ramanuja, one of the great philosophers of Hinduism who lived during the eleventh and twelfth centuries A.D. Ramanuja turned the tables on Brahman and argued that the impersonal nature of God was secondary to the personal, and Ishwara (whom he identified with the second god in the Hindu trinity, Vishnu, the god of preservation) is Ultimate Reality. There is thus a theistic school within Hinduism, although this version of theism is panentheist (known as Vishishtadvaita or qualified monism), meaning that everything exists within God, but everything is not God. In other words, the world and souls are real but they are also part of God’s being, not separate from Him, as in Christianity.
In the sixteenth century, a bhakti yogi named Chaitanya (or Caitanya) went a step further and argued that Krishna, who was believed to be an avatar (incarnation or manifestation) of Vishnu, actually is just another name for Vishnu and that Krishna is thus the supreme personality of the Godhead. The Hare Krishna cult (the International Society of Krishna Consciousness, or ISKCON), fully within Chaitanya’s movement, provides a good example of bhakti yoga in the West, with its devotional dancing, chanting, and singing of the names of Krishna, as well as its worship and ritualized care of its “deities” (idols).