“Spiritual revolutionaries must be committed not to what is easiest, but to what is most beneficial to themselves and the world.”

Book of Taliesin (c. 1275?), The First Address of Taliesin

Spanish: Sobre todo, sean siempre capaces de sentir en lo más hondo cualquier injusticia cometida contra cualquiera en cualquier parte del mundo. Es la cualidad más linda de un revolucionario.
Letter to his Children (1965)

Source: The Net of Faith (c. 1443), Chapter 95

54
The Zürau Aphorisms (1917 - 1918)
Context: There is nothing besides a spiritual world; what we call the world of the senses is the Evil in the spiritual world, and what we call Evil is only the necessity of a moment in our eternal evolution.
One can disintegrate the world by means of very strong light. For weak eyes the world becomes solid, for still weaker eyes it seems to develop fists, for eyes weaker still it becomes shamefaced and smashes anyone who dares to gaze upon it.

Third Olynthiac http://books.google.com/books?id=n4INAAAAYAAJ&q="the+easiest+thing+in+the+world+is+self-deceit+for+every+man+believes+what+he+wishes+though+the+reality+is+often+different"&pg=PA57#v=onepage, section 19 (349 BC), as translated by Charles Rann Kennedy (1852)
Variants:
A man is his own easiest dupe, for what he wishes to be true he generally believes to be true.
As quoted in The Routledge Dictionary of Quotations (1987) by Robert Andrews, p. 255
There is nothing easier than self-delusion. Since what man desires, is the first thing he believes.

[George Sarton, A guide to the history of science: a first guide for the study of the history of science, with introductory essays on science and tradition, Chronica Botanica Co., 1952, 3]