Sincerity is not enough. Every aspirant needs this, of course, but he also needs other things. An aspirant may be totally sincere, yet may take a wrong direction. His mind may be filled with erroneous beliefs despite his sincerity. So to his sincerity he should add right knowledge, for this will guide him, this will uphold him, and this will safeguard him.
-- Notebooks Category 7: The Intellect > Chapter 2: The Service of Intellect > # 55