From Notes Of Class Talks And Lectures of Volume 6 of The Complete Works of Swami Vivekananda
First, meditation should be of a negative nature. Think away everything. Analyse everything that comes in the mind by the sheer action of the will.
Next, assert what we really are — existence, knowledge, and bliss — being, knowing, and loving.
Meditation is the means of unification of the subject and object. Meditate:
Above, it is full of me; below, it is full of me; in the middle, it is full of me. I am in all beings, and all beings are in me. Om Tat Sat, I am It. I am existence above mind. I and the one spirit of the universe. I am neither pleasure nor pain.
The body drinks, eats, and so on. I am not the body. I am not mind. I am He.
I am the witness. I look on. When health comes I am the witness. When disease comes I am the witness.
I am Existence, Knowledge, Bliss.
I am the essence and nectar of knowledge. Through eternity I change not. I am calm, resplendent, and unchanging.