Lord Krishna and Yoga
The Bhagavad Gita presents, as its main content, a dialogue between Krishna and the Pandava hero Prince Arjuna on the meaning of life. This dialogue takes place before the great Mahabharata battle on the holy field of Kurukshetra. Krishna explains the nature of the immortal Self - the Atman - and the proper way to reach the Brahman. Krishna maintains that people must shed the burden of karma, or residual blameworthiness, for wrongs committed in their present and former lives.
Krishna assures Prince Arujna that the Self, (Atman) cannot kill or be killed, once a human body expires the Self previously contained therein becomes available for reincarnation according to its merits or demerits in terms of karma. Krisha urges that given this reincarnation it would worse for Prince Arujna to decline the battle than to fail in his duties as a warrior.
Krishna outlines three approaches towards union with God.
Karma Yoga - the Way of Action
Jnana Yoga - the Way of Knowledge
Bhakti Yoga - the Way of Devotion
Each person should do his or her duty with faith and without hope of personal benefit or ambition. This faith and this disinterestedness act to purge people following Karma Yoga of their burden of karma. Faithless and self-interested actions would tend to increase that burden. Only by shedding the burden of karma can people hope to achieve release from an endless cycle of births, deaths, and rebirths into lives involving suffering.
Jnana Yoga allows people to seek union with God through contemplation, meditation, and the realisation that the Self (Atman) and the World-Soul (Brahman) are One.
Under Bhakti Yoga Krishna may be worshipped as a spirit or as an image by his followers. Every worshipper who approaches with a sincerely loving heart is fully accepted. Krishna will accept any offering, be it little or be it great, as long as it is made with love. Union with Brahman, and release from the suffering inherent to the otherwise endless cycle of births, deaths, and rebirths, can be attained through sincere devotion to Krishna.