Ramakrishna knew that Narendra’s mind was naturally inclined to the path of knowledge, so he initiated him into the teachings of nondualistic Vedanta. Sometimes he asked Narendra to read aloud passages from the Ashtavakra Samhita and other Vedanta treatises so that he could grasp the essence of the Vedanta philosophy, which teaches that Brahman is the ultimate Reality, existence-consciousness-bliss absolute. The individual soul is Brahman and nothing else. The world is shown to be nothing but name and form, all of which is apparent, not real, having only a relative existence.
In the beginning it was hard for Narendra to accept the nondualistic view that “everything is really Brahman,” because he was then a staunch follower of the Brahmo Samaj, which taught a theistic philosophy. He said to the Master: “It is blasphemous, for there is no difference between such philosophy and atheism. There is no greater sin in the world than to think of oneself as identical with the Creator. I am God, you are God, these created things are God — what can be more absurd! The sages who wrote such things must have been insane.” The Master didn’t mind Narendra’s outspokenness at all. He smiled and said: “You may not accept the views of these seers. But how can you abuse them or limit God’s infinitude? Go on praying to the God of Truth and believe in any aspect of His that He reveals to you.”
One day while chatting with Hazra at Dakshineswar, Narendra ridiculed the Vedantic experience of oneness: “How can this be? This jug is God, this cup is God, and we too are God! Nothing can be more preposterous!” When the Master heard Narendra’s comment from his room, he came out and inquired: “Hello! What are you talking about?” Ramakrishna touched Narendra and went into samadhi. Later Narendra graphically described the effect of that touch:
The magic touch of the Master that day immediately brought a wonderful change over my mind. I was stupefied to find that there was really nothing in the universe but God! I saw it quite clearly but kept silent, to see if the idea would last. But the impression did not abate in the course of the day. I returned home, but there too, everything I saw appeared to be Brahman. I sat down to take my meal, but found that everything — the food, the plate, the person who served, and even myself — was nothing but That. I ate a morsel or two and sat still. I was startled by my mother’s words: “Why do you sit still? Finish your meal,” and began to eat again. But all the while, whether eating or lying down, or going to college, I had the same experience and felt myself always in a sort of comatose state. While walking in the streets, I noticed cabs plying, but I did not feel inclined to move out of the way. I felt that the cabs and myself were of one stuff. There was no sensation in my limbs, which, I thought, were getting paralyzed. I did not relish eating, and felt as if somebody else were eating. Sometimes I lay down during a meal, after a few minutes, got up and again began to eat. The result would be that on some days I would take too much, but it did no harm. My mother became alarmed and said that there must be something wrong with me. She was afraid that I might not live long. When the above state altered a little, the world began to appear to me as a dream. While walking in Cornwallis Square [now Azadhind Bag], I would strike my head against the iron railings to see if they were real or only a dream. This state of things continued for some days. When I became normal again, I realized that I must have had a glimpse of the Advaita [nondual] state. Then it struck me that the words of the scriptures were not false. Thenceforth I could not deny the conclusions of the Advaita philosophy. (Source: God Lived with Them)