The problem of philosophic attainment is one which man cannot solve by his own unaided powers. Like a tiny sailing boat which needs both oars and a sail for its propulsion, he needs both self-effort and grace for his progress. To rely on either alone is a mistake. If he cannot attain by his own strivings, neither is the Overself likely to grant its grace without them.

-- Notebooks Category 2: Overview of Practicies Involved > Chapter 9: Conclusion > # 18