"Pray, hope, and don't worry" is associated with Padre Pio of Pietrelcina (1887–1968), the Italian Franciscan friar and mystic who was canonized by Pope John Paul II in 2002.  The phrase reflects the core of Padre Pio's spiritual counsel, which he offered constantly to the thousands of people who sought him out for guidance. He believed that anxiety and worry were obstacles to faith, and that genuine trust in God — expressed through prayer and hope — was the remedy. He often expanded on the idea by emphasizing that worry was not only useless but spiritually harmful, since it implied a lack of trust in divine providence.
 
Padre Pio was known for his mystical gifts — reportedly bearing the stigmata for 50 years — and his enormous pastoral influence drew pilgrims from across the world. His practical, warm approach to spiritual guidance made phrases like this one stick, and it remains one of the most recognized expressions of Catholic spiritual wisdom today.