“We know that the simplistic, almost childlike naivety or perhaps the intellectual senility of the architects of this concept have not taken into consideration the practical difficulties and impracticalities of sharing power for the sake of sharing power in our society with political parties that are diametrical opposed to each other.”

From books
Source: Jean Vanier, Community And Growth, 1979

Source: What is to be Done? (1902), Chapter Three, Section E, Essential Works of Lenin (1966)

As quoted in Bringing Out the Best in Everyone You Coach : Use the Enneagram System for Exceptional Results (2009) by Ginger Lapid-Bogda, p. 123

Collected Works, Vol. 26, pp. 304–308.
Collected Works

"The Loss of the Future"
The Long-Legged House (1969)

This has been attributed to Crowley on the internet, but without citation. No incidents of it in Crowley's works have as yet been located.
This was quoted as an "occult tradition" in Fundamentals of Experimental Psychology (1976) by Charles Lawrence Sheridan, p. 17, but without any reference to Crowley.
Disputed
Variant: Knowledge is power and knowledge shared is power lost.

We have lived and loved together, reported in Bartlett's Familiar Quotations, 10th ed. (1919).

"The Loss of the Future".
The Long-Legged House (1969)
Context: A community is the mental and spiritual condition of knowing that the place is shared, and that the people who share the place define and limit the possibilities of each other's lives. It is the knowledge that people have of each other, their concern for each other, their trust in each other, the freedom with which they come and go among themselves.

"What Is Empathetic Superintelligence?" https://www.abolitionist.com/transhumanism/index.htm presentation, 29 Jan. 2011