Whenever there is sincerity, you find that the help, the guidance, the grace are always there to give you the answer and you are not mistaken for long. It is this sincerity in the aspiration for progress, in the will for truth, in the need to be truly pure—pure as it is understood in the spiritual life—it is this sincerity which is the key to all progress. With it you know—and you can.
Ref: Questions and Answers 1929–1931