Peale distilled the optimism and self-sufficiency of the American character into a simple creed. The first article of his faith was a warm patriotism. He called the U.S. “the greatest country in the world” and addressed his writing to “everyday people of this land” who “are my own kind whom I know and love and believe in with great faith.” These were the people he met in masonic halls, resort hotels, and cruise-ship conference rooms. In them he sensed innate decency and ability. Any one of them could become efficient and successful—if only he would believe in himself, harnessing the power of positive thinking.

Peale promised his readers “constant energy” if they thought positively. Optimistic thoughts opened one up to a vital force coming directly from God. Negative thoughts, especially a tendency to dwell on one’s faults, could interfere with the divine charge. He warned those with active consciences that “the quantity of vital force required to give the personality relief from either guilt or fear” was so great that it left “only a fraction of energy” for going about one’s tasks. Productivity and cheeriness became for him the signs of eternal election. (In attacking Jeb Bush for being “low-energy,” Trump effectively accused him of having forfeited the Holy Ghost.)

—Matthew Schmitz