Bhgavad Vita precisely described the all of the spiritual paths of the Hindu when he said, “Yoga is the journey of the self to the self through the self”. That discovery comes in 4 separate and distinct forms. Common American perception is that the practice of yoga is primarily a physical practice separate and apart from religion. “The word yoga derives from the same root as does the English word yoke; meaning to unite and place under disciplined training”. Americans take this definition literally and only consider the physical aspect of yoga training. This approach leads to a gap in the most enlightening aspects of yoga; spiritual training. Like many of the world’s religions Hinduism has one distinct goal and that is to unite the human spirit with God. Hindu’s believe that there are 4 separate paths to reaching enlightenment and uniting your spirit with God via the spiritual and physical discipline that is yoga. Because of the variety and complexity of the human personality, Hinduism understands that we all approach our spirituality from different points in life. The focus of the four paths is on the strongest aspect of the personality with the ultimate goal of “rendering the surface self-transparent to its underlying divinity; cleansed of its gross impurities”. The four paths of yoga are Jnana Yoga (the path through knowledge), Bhakti Yoga (the path through love), KarmaYoga (the path through work), and Raja Yoga (the path of the psychophysical). Jnana Yoga is considered the yoga for the rational. It is said that Jnana has the strongest reflective element of all of yoga. Jnana yoga uses the rational focus, detached from emotion, to evaluate who we are and how that shapes our experiences. Bhatki Yoga is considered the yoga of love and devotion to God. Because it is considered the yoga of inner purification, Bhatki Yoga requires cleansing of the ego and has the steepest and shortest path to unity with the divine. Karma yoga is often referred to as the path of work or selfless devotion. Because Karma Yoga is the yoga of action it can be practiced through Jnana (knowledge) yoga or Bhatki (love) yoga. The final yoga is fondly referred to as the “royal road”. The comprehensive psychophysical yoga approaches unity with all facets and disciplines of the other three yoga paths. For those who are scientifically inclined, this is the yoga of choice. In an effort to seek unity with God, Hindus practice in ways that are commonly seen in other religions. The chanting/mantras of the bhakti yoga are reminiscent of Pentecostal Christian practices that focus on the “feeling” of the religious experience demonstrated by speaking in tongues, going into trances and seeing visions. Many would liken the recitation of Hindu chants to that of a Church Revival Meeting because of the emotional and physical response these both evoke. Like many faiths, Hinduism is steeped in deep and varied rituals to include chants and meditations along with offerings of milk and fruit. Religious ceremonies that are common in a variety of faiths have the same formal and ritualistic service in yoga. Yogi Bhajan captures the intent of yoga when he said, “the attitude of gratitude is the highest yoga”.
References

Smith, Huston (1958). The World's Religions. New York City: Harper Collins.