Yoga is the practical aspect of the inner side of man’s religion. The outer side of religion in its institutionalized and organized social aspect is its traditional form, made up of the periodical common or collective worship, be it in church, synagogue, mosque, temple or prayer house; its sacraments, ceremonial, ritual, etc. Whereas the inner side of religion in its deeply personal aspect of the individual’s effort to spiritually progress towards God and obtain vital religious experience is termed Yoga.
The practice of Yoga implies and constitutes your sincere attempt to realize the ultimate truths of your religion as actual personal experience. Religion as an organized outer structure is a social phenomenon. And religion as an inner discipline and daily practice is its systematic mystical dynamics, is a spiritual phenomenon. The entire practice of Yoga is verily this universal latter part of religion just refered to above. These two terms, religion and Yoga, are almost identical in their meaning. The term "religion" is of Latin origin, meaning the re-linking or binding man to God. The term "Yoga" is of Sanskrit origin, meaning uniting man’s spirit with the Divine Spirit or God.
The special feature to be noted regarding Yoga is that it represents the universal spiritual mystic that underlies all religions of mankind, and is therefore a common and thus unifying factor in the religious life of human society. Whereas, as an observed historical phenomenon, the diversified religious systems have tended to separate man from man and split up human society into mutually exclusive groups that refuse to harmonize with one another.
Yoga tends to bring out the inner unity that exists at the central core of all religions, and its non-sectarian techniques bring people closer in spiritual ties of inner unity. Yoga is to religion what food and eating are to the science of nutrition. Yoga is to religion what actual physical exercise is to the subject of physical culture and national health. Yoga is a scientific methodology of religion and Yoga practice guides the Yoga follower in the path of practical religion towards the true goal of all religion, namely God-experience.
Yoga constitutes man’s purposeful movement towards God, which actually comprises the very quintessence of all religion. This surely is the truth about Yoga. While Yoga divides its practices to suit the different temperaments and capacities of the various individuals, it declares at the same time the indivisible oneness of the aim of all religious life, and the oneness of the goal of all religious strivings, namely God—the Universal Spirit—who is addressed by various names like Jehovah, Allah, Almighty Father, etc. Yoga and religion are inseparable if you understand them right.
Minus Yoga, religion would be but a dead shell lacking spiritual substance. Yoga is the unfolding process of practical religion, the inner personal religious life of each individual. It enriches your religious life, makes you a better human individual, and elevates the standard of human conduct and behaviour upon all levels of human relationship.