"Unity in variety is the plan of the universe," Vivekananda observed. "As a man you are separate from an animal, but as living beings man, woman, animal, and plant are all one; and as existence you are the whole universe. That universal existence is God, the ultimate Unity in the universe. In him we are all one. At the same time, in manifestation these differences must always remain."
"What then," he asks, "do I mean by the ideal of a universal religion? I do not mean any one universal philosophy, or any one universal mythology, or any one universal ritual, held alike by all; for I know that this world must go on working, wheel within wheel, this intricate mass of machinery, most complex, most wonderful. What can we do then? We can make it run smoothly, we can lessen the friction, we can grease the wheels as it were. How? By recognizing the natural necessity of variation. Just as we have recognized unity by our very nature, so we must also recognize variation. We must learn that truth may be expressed in a hundred thousand ways, and that each of these ways is true so far as it goes. We must learn that the same thing can be viewed from a hundred different standpoints and yet be the same thing."
[Vidyatamananda and Isherwood, "What Religion Is," pp. 30-31.]
The non-dualistic universality of Swami Vivikenanda's message is an eternal theme of the great visionaries and mystics of all traditions. In the attached video, this theme is reiterated in the words of the great thirteenth-century Sufi poet, Jalalludin Rumi.