The teachers of the science of yoga declare that religion is not only based upon the experience of ancient times, but that no one can be religious until one has the same perceptions oneself. Yoga is the science which teaches us how to get these perceptions. It is not of much use to talk about religion until one has felt it. Why is there so much disturbance, so much fighting and quarreling in the name of God? There has been more bloodshed in the name of God than for any other cause, because people never went to the fountainhead; they were content only to give mental assent to the customs of their forefathers and wanted others to do the same. What right has one to say one has a soul if one does not feel it, or that there is a God if one does not see Him? If there is a God we must see Him, if there is a soul we must perceive it. . . One wants truth, wants to experience truth for him or herself. When one has grasped it, realized it, felt it within one’s heart of hearts, then alone, declare the Vedas, will all doubts vanish, all darkness be scattered, and all crookedness be made straight. ‘Ye children of immortality, even those who live in the highest sphere, the way is found. There is a way out of all this darkness, and that is by perceiving Him who is beyond all darkness; there is no other way.’
The science of Raja Yoga proposes to put before humanity a practical and scientifically worked out method of reaching this truth. . . Each science must have its own methods. I could preach you thousands of sermons, but they would not make you religious, until you practiced the method. These are the truths of the sages of all countries, of all ages, of those who are pure and unselfish, who had no motive but to do good to the world. They all declare that they have found some truth higher than what the senses can bring to us, and they invite verification. They ask us to take up the method and practice honestly, and then, if we do not find this higher truth, we will have the right to say there is no truth in the claim, but before we have done that, we are not rational in denying the truth of their assertions. So we must work faithfully, using the prescribed methods, and light will come.
– Swami Vivekananda, Raja Yoga (Patanjali’s Yoga Sutras)