One thing alone is needful, the salvation of one’s soul. What doth it profit a man to gain the whole world if he suffer the loss of his immortal soul? Ah, my dear boys, believe me there is nothing in this wretched world that can make up for such a loss.
 James Joyce, A Portrait of the Artist as a Young Man (1916). copy citation

Context

“We shall try to understand them fully during these few days so that we may derive from the understanding of them a lasting benefit to our souls. And remember, my dear boys, that we have been sent into this world for one thing and for one thing alone: to do God’s holy will and to save our immortal souls. All else is worthless. One thing alone is needful, the salvation of one’s soul. What doth it profit a man to gain the whole world if he suffer the loss of his immortal soul? Ah, my dear boys, believe me there is nothing in this wretched world that can make up for such a loss. —I will ask you, therefore, my dear boys, to put away from your minds during these few days all worldly thoughts, whether of study or pleasure or ambition, and to give all your attention to the state of your souls.” source