Pope John XXIII
Mater et Magistra §247
Mater et Magistra: On Christianity and Social Progress
247 May these warning words of the divine Master ever sound in men's ears: "For what doth it profit a man, if he gain the whole world and suffer the loss of his own soul? Or what exchange shall a man give for his soul?" (51)
Source: Mater et Magistra (Vatican.va)