Sadhaka : What is the relation between Yoga and religion? Can I practise Yoga, even if I am not a Hindu?
Gurudev : Yoga is for all, and (it) is universal. It is not a sectarian affair but a way to God, and not a creed. Yoga is union with God, union with all. God dwells in all. The practice of Yoga is not opposed to any religion or any sacred Church. It is purely spiritual and does not contradict anyone's faith. Yoga is not a religion, but an aid to the practice of the basic spiritual truths in all religions. Yoga is for all, and is universal. It is not a sectarian affair but a way to God. To live in God, to commune with God is Yoga.
Swamiji : Yoga is one of the six systems of philosophy. Yoga is a universal science that has risen above religion. It is a universal technique. No particular dogma is laid down, and no particular god is pointed out for your worship. Yoga does not say that you must repeat any particular name of God. Yoga only says that repetition of one of the Divine name is one of the ways of concentrating the mind. It does not specify the name or whom to worship.
Yoga is the heritage of humanity. The application of Yoga is universal. Yoga can be applied to any religion. In no way Yoga contradicts your religion or anything. Yoga is a science of man. It brings him to the supreme Experience. In each religion there is a certain spiritual content, which has direct relevance with that part of you which is your innermost essential being. The prime concern of Yoga is the spiritual Reality within you, the attainment of the spiritual goal for which you have taken this human birth. Yoga is the path to God-realisation. Yoga is the path of Divine Experience, which is the inner core of religion. Yoga comes as life-giving waters to revive that withering inner spiritual core that has been neglected and dried away. Thus, it makes your religion alive for you. Yoga restores to people the inner spiritual content of their religion.
In what way does it differ (from religion)? It does not call a man sinner. Man is God who has lost his way home, who is stumbling and running about in circles. It puts the man on the path again, shows the light, and days; "go ahead now, go straight to your home." Yoga rejects hell and heaven also. Heaven is also a petty desire. You don't want it. Yoga concerns itself with God, not heaven or hell.
The highly evolved and practical techniques of Yoga may be applied by all races, nations, castes, creeds, churches and sects. This body of practical techniques stands out distinct and entirely separate from all those metaphysical concepts in the background. Yoga transcends religion, it is supra-religious. Yoga is far removed from any dogma or doctrine. All the great Christian saints and mystics who have sincerely tried to love and worship God, and contemplate upon Him and realised their oneness with Him would be yogis. Saint Augustine was a great Bhakti-yogi and Jnana-yogi combined. Saint John of the Cross, and Saint Teresa of Avila were both great Raja-yogis.