Bhakti as a process of yoga (Bhakti yoga) is described in detail famously within the Bhagavad Gita, wherein it is given as the ultimate form of religious expression, for which all other dharmas and also in other texts such as the Narada Bhakti Sutra. should be abandoned
By Patanjali's time (2nd century BC) there appear to have been "followers of Vasudeva".
The term bhakti in the sense of "devotion" emerges in Puranic literature.
The Alvars were influential to the emergence of the Bhakti movement, which between the 13th and 17th centuries brought about the revival of Shaivism in Southern India and gradually grew into the various branches known today.
The ultimate goal
The forces that cause creation sustain and maintain that which has become created and eventually cause the destruction of that which was created – named Brahman, by the Upanishads – permeate everything in the Creation. Brahman is the self creating force that is in all that has a name and form as well as that which remains formless and nameless.
The Bhagavata Purana describes three different levels of Brahman realisation. The first is an impersonal state of blissful consciousness, similar to nirvana where one is aware of the great universal Brahman effulgence permeating everything; the second is classified as Paramatmaatma); the third and ultimate realisation is described as Bhagavan, in this state one has a direct loving relationship with The Supreme Personality of Godhead himself, in one or more of His transcendental forms. realisation, wherein one is actually able to see the Form of Godhead alongside one's own soul (
The main difference between bhakti philosophy and all others is that the goal is also the means of attaining the goal. In other words, bhakti, devotional service to the Supreme, is attained by engaging in devotional service to the Supreme. The difference between the starting and concluding stages is that in the beginning the activity of bhakti is a forced engagement, whereas in the conclusion it is a spontaneous, loving reciprocation. 
 Archana: Deity worship
The Smarta tradition of Hinduism recommends that each person may choose a deity of worship (ishta-devata) to which they are most attracted. If the grossest manifestation is the only thing that suits one’s taste, or mood, or psychological make-up or intellect, one is free to worship God in that form, as long as the form itself is bonafide and from scripture (not imaginary). It is in this spirit that Sahasranama stotras (1000 names of God) and ashtottara-stotras (poems of praise through 108puranas though they extoll different deities. names) are found in abundance in Hindu religious literature for almost every deity. It is this train of thought in the Smarta Hindu mind that lives with different
In contrast, the Vaishnava tradition teaches that only Vishnu is to be worshipped. Meanwhile, the Saivite tradition teaches that only Shiva is to be worshipped.
In addition, the choice of ishta-devata became, over the centuries, a choice of one among the thousands of temples scattered throughout the country and the deity chosen may very well be the particular deity enshrined in a specific temple, though certainly belonging to one of the six major streams listed above.
It is this variety and possibility of ‘to each according to his needs and capabilities’ that brings together under one banner of Hinduism people with varying practices, attitudes and states of evolution. Accordingly carving of images of deity forms both for worship at home and in the temples became one of the most highly developed art and profession in India. The religious life of India was thus nourished through the ages on a visual statement, unmatched perhaps, in the history of civilization.
Classifications of Bhakti
The scripture known as the Narad Bhakti Sutra, believed to be spoken by the sage Narada distinguishes eleven forms of bhakti based on the different relationship to God that the devotee can assume.
The devotee Prahlada, as explained in Srimad Bhagavatam, enunciates Nine Expressions of Bhakti. See also Bhakti yoga.
According to Adi Shankara, bhakti is the seeking after one's real nature. Adi Shankara, in verse 61 of his Sivanandalahari lists five analogies of Bhakti. See Five Graded Analogies of Bhakti.
Further detail classification of bhakti is presented by Rupa Goswami in his Bhakti-rasamrita-sindhu.
Bhakti as a term is sometimes found in other Indic religions and in some sects of Buddhism.
Theory of divine grace
In any theory of grace it is the surrender to God’s will and humility that matters. The practitioner has to surrender by their own free will with the understanding that living people have the free will to obey or disobey God. The fatalist view of reality is only a fragmentary part of Hinduism. A person's fate is reflected mainly in the tendencies that he has created for himself through committed actions. He has total free will to surrender to God or not. But if he surrenders to Him heart and soul, He promises that He will take care of his pure devotee. This is famously illustrated in one of Krishna's final statements to Arjuna in the Bhagavad Gita:
- "Abandon all varieties of religion and just surrender unto Me. I shall deliver you from all sinful reactions. Do not fear". (Bhagavad Gita 18.66)