“The words ‘mysticism’ and ‘mystical’ are often used as terms of mere reproach, to throw at any opinion which we regard as vague and vast and sentimental, and without a base in either facts or logic.”
- The Varieties of Religious Experience, p. 413 - 14; (orig. 1902; Modern Library Paperback Ed. 2002)

“There are, of course, other dimensions and ultimate realities that are well represented by adepts, trance readers, channelers, psychics, clairvoyants, shamans, magicians … erstwhile guides … fortune tellers, card readers, astrologers, throwers of Rune stones, and more. To add to the glamour, many of these diversions have large collections of faithful followers and enthusiasts who are impressed and thereby influenced, as well as seduced, by the magical notion of the unseen paranormal. Also popular are ‘ancient secret mysteries’, UFO religions, primitive rites, magic symbols, crystals, incantations, energy manipulation, and spirits from other realms.
Classical spiritual tradition and integrous scripture do not refute the supernatural/paranormal, but warn ‘not to go there’. The same advice is also prescribed by all true spiritual masters and enlightened teachers …
Fortunate is the seeker who has not been led away from the straight and narrow path by diversions and popularized attractions … These are delays and also traps for the unwary. Their appeal is to the exotic, foreign, occult, and esoteric elaborations that are intriguing but do not lead to Enlightenment. Most are merely imitations of the genuine phenomena … Spiritual fairy tales abound and impress the credulous for whom anything labeled ‘spiritual’ is imbued with a magical glamour … There is no lack of integrous, reliable spiritual truth accessible by ordinary means. Thus, the seeking of the extraordinary is a trap for the unwary. An ego that is ‘out of body’ is actually just the same as an ego in a body, except that it now has the mystification of being physically elusive.”
- Discovery of the Presence of God pgs. 93 - 97; (2007)

“What then do we really mean by mysticism? A word which is impartially applied to the performances of mediums and the ecstasies of the saints … to sorcery, dreamy poetry and mediaeval art, to prayer and palmistry … even, according to William James, to the higher branches of intoxication — [it] soon ceases to have any useful meaning. Its employment merely confuses the inexperienced student, who ends with a vague idea that every kind of super-sensual theory and practice is somehow “mystical.” Hence the need of fixing, if possible, its true characteristics: and restating the fact that Mysticism, in its pure form, is the science of ultimates, the science of union with the Absolute, and nothing else, and that the mystic is the person who attains to this union, not the person who talks about it. Not to know about, but to Be, is the mark of the real initiate.”
- p. 42

“Mysticism … is essentially a movement of the heart, seeking to transcend the limitations of the individual standpoint and surrender itself to ultimate Reality; for no personal gain, to satisfy no transcendental curiosity, to obtain no other-worldly joys, but purely from an instinct of love. By the word heart, of course, we here mean not merely ‘the seat of the affections,’ ‘the organ of tender emotion,’ and the like: but rather the inmost sanctuary of personal being, the deep root of its love and will, the very source of its energy and life. The mystic is ‘in love with the Absolute’ not in any idle or sentimental manner, but in that vital sense which presses at all costs and through all dangers towards union with the object beloved.”
- pgs. 71-72

“The business and method of Mysticism is Love … the ultimate expression of the self’s most vital tendencies.”
- p. 85

“Mysticism may be looked upon as the final term, the active expression, of a power latent in the whole race: the power, that is to say, of so perceiving transcendent reality. Few people pass through life without knowing what it is to be at least touched by this mystical feeling. He who falls in love with a woman and perceives — as the lover really does perceive — that the categorical term “girl” veils a wondrous and unspeakable reality: he who, falling in love with nature, sees the landscape “touched with light divine,” — a charming phrase to those who have not seen it, but a scientific statement to the rest — he who falls in love with the Holy, or as we say “undergoes conversion”: all these have truly known for an instant something of the secret of the world.”
- p. 73

All quotes from:
Mysticism: A Study in the Nature and Development of Man’s Spiritual Consciousness (orig. 1920; 1974 ed.)

“Mysticism is the experience, not talking or thinking about it, but the actual experience of oneness with all. That is basically the core of all mystic experience, that we belong to that great mystery with which we are most strangely also at the same time confronted. We belong to it, and we are confronted with it. So every human being has a mystic experience and one can really say the mystic isn’t that special kind of human being. But every human being is a special kind of mystic.”
- “Reflections” video from A Network for Grateful Living: https://gratefulness.org/reflections/

“I is consciousness. I is God. I is pure Awareness. Imagine if you will, whenever you said ‘I’ you realized truly what this I means to you. You’re no longer speaking of the small I, the body I, the I that does not exist. You’re speaking of God. Whenever you say ‘I,’ you’re speaking of God.”
- Silence of the Heart, p. 32

“There is only one I actually. That I is Consciousness. When you follow the personal I to the source, it turns into the universal I, which is Consciousness.”
- Silence of the Heart, p. 36

“Whenever you have a problem, I don’t care what it is, I don’t care how serious you think it is, whether it’s personal or worldly, wherever it came from … It makes no difference, because it is God who is going through this, not me. And God has no problems. You automatically become happy, just by using the I Am meditation.”
- Silence of the Heart, p. 101-102

Selections from Episode 8 explaining the I Am Meditation are also taken from Silence of the Heart, pgs. 101-104

“My me is God, nor do I recognize any other Me except my God Himself.”
- encountered in The Perennial Philosophy by Aldous Huxley, p. 11

“Do not search for God outside of you. God can only be found within you, for His only abode is the heart.”
- The Everything and the Nothing, p. 7

“To be unselfish, perfectly selfless, is salvation itself; for the man within dies, and God alone remains.”
- The Complete Works of Swami Vivekananda, p. 1560; (Orig. 1947; Manonmani Publishers 2015 ed.)

“Let us do good because it is good to do good; he who does good work even in order to get to heaven binds himself down.”
- Karma Yoga: The Yoga of Action, p. 86

“You are incarnations of God, all of you. You are incarnations of the Almighty, Omnipresent, Divine Principle. You may laugh at me now, but the time will come when you will understand. You must. Nobody will be left behind.”
- The Complete Works of Swami Vivekananda, p. 2096; (Orig. 1947; 2018 ed.)

“The day of my spiritual awakening was the day I saw and knew I saw all things in God and God in all things. I who am Divine am truly in you … I am in you and you are in Me, we could not be any closer. We two are fused into one.”
- Meditations with Mechtild of Magdeburg by Sue Woodruff, p. 42 (1982)

“I know of an officer on our police force who has told me that many times when off duty, and on his way home in the evening, there comes to him such a vivid and vital realization of his oneness with this Infinite Power, and this Spirit of Infinite Peace so takes hold of and so fills him, that it seems as if his feet could hardly keep to the pavement, so buoyant and so exhilarated does he become by reason of this inflowing tide.”
- In Tune with the Infinite, p. 137 (as encountered in William James The Varieties of Religious Experience, p. 429 [2002 ed.])

“Our Lord opened my spiritual eye and showed me my soul in the middle of my heart, and I saw the soul as wide as if it were an infinite world, and as if it were a blessed kingdom.”
- Ecstatic Confessions: The Heart of Mysticism, p. 95; (orig. 1909; 1985 ed.)

“... in an instant I saw myself wholly united with God, transformed into God, and outside all bodily feeling, so that I would have felt nothing if I had been thrown into a fiery furnace. I did not know whether I was dead or alive, in the body or in the soul, on earth or in heaven; I saw only the whole glorious God in himself, loving himself purely, knowing himself infinitely, embracing all created things in pure infinite love … a God of boundless love, all-exalted in goodness, incomprehensible and unfathomable; so that I was with him and found nothing more of myself; only this I saw, that I am in God; but I did not see myself, only God alone.”
- Ecstatic Confessions: The Heart of Mysticism, pgs 110-111; (orig. 1909; 1985 ed.)

“He saw and knew that the Cosmos is not dead matter but a living Presence, that the soul of man is immortal, that the universe is so built and ordered that without any peradventure all things work together for the good of each and all, that the foundation principle of the world is what we call love, and that the happiness of everyone in the long run is absolutely certain. I learned more within the few seconds that illumination lasted than in all my previous years of study and I learned much that no study could ever have taught.”
- Dr. Bucke gives his account in the third person; here it is rendered in the first person, as formulated here

“… a sense of immortality, a consciousness of eternal life, not a conviction that he shall have this, but the consciousness that he has it already.”
- p. 3

Both quotes from:
Cosmic Consciousness (orig. 1901; Arkana Books 1991 ed.)

“Suddenly … my spirit did break through … and I was embraced with love, as a bridegroom embraces his dearly beloved bride. But the greatness of the triumphing that was in the spirit I cannot express either in speaking or writing; neither can it be compared to anything, but with that wherein the life is generated in the midst of death, and it is like the resurrection from the dead. In this light my spirit suddenly saw through all, and in and by all the creatures, even in the herbs and grass, it knew God, who he is, and how he is, and what his will is.”
- encountered in Cosmic Consciousness by Richard Maurice Bucke, p. 185 (orig. 1909; Arkana Books 1991 ed.)
I believe the quote originates from ‘The Life of Jacob Behmen’

“Is the story, sung by mystics and sages the world over, any crazier than the scientific materialism story, which is that the entire sequence is a tale told by an idiot, full of sound and fury, signifying absolutely nothing? Listen very carefully: just which of those two stories actually sounds totally insane?”
- A Brief History of Everything, p. 42

“You know it beyond a shadow of a doubt.”
- encountered here

“The spiritual life justifies itself to those who live it; but what can we say to those who do not understand? This, at least, we can say, that it is a life whose experiences are proved real to their possessor, because they remain with him when brought closest into contact with the objective realities of life. Dreams cannot stand this test. We wake from them to find that they are but dreams. Wanderings of an overwrought brain do not stand this test. These highest experiences that I have had of God’s presence have been rare and brief — flashes of consciousness which have compelled me to exclaim with surprise — God is here! — or conditions of exaltation and insight, less intense, and only gradually passing away. I have severely questioned the worth of these moments. To no soul have I named them, lest I should be building my life and work on mere phantasies of the brain. But I find that, after every questioning and test, they stand out today as the most real experiences of my life, and experiences which have explained and justified and unified all past experiences and all past growth. Indeed, their reality and their far-reaching significance are ever becoming more clear and evident. When they came, I was living the fullest, strongest, sanest, deepest life … It was in the most real seasons that the Real Presence came, and I was aware that I was immersed in the infinite ocean of God.”
- My Quest for God, p. 256-257; (1897)
Encountered in The Varieties of Religious Experience, p. 433 (orig. 1902; Modern Library Paperback Ed. 2002)

“True religion being the greatest thing in life and in the world, it has been exploited the most. And those who have seen the exploiters and the exploitation and missed the reality naturally get disgusted with the thing itself. But religion is after all a matter for each individual, and then too a matter of the heart, call it then by whatever name you like, that which gives one the greatest solace in the midst of the severest fire is God.”
- from a letter to Jawaharlal Nehru: April 25, 1925;
as collected in The Essential Gandhi: An Anthology of His Writings on His Life, Work, and Ideas, p. 186

“What I want to achieve – what I have been striving and pining to achieve … is self-realization, to see God face to face, to attain Moksha. I live and move and have my being in pursuit of this goal. All that I do by way of speaking and writing and all my ventures in the political field are directed to this same end.”
- The Story of My Experiments with Truth (Gandhi’s autobiography) from the introduction, p. xiv