It is necessary to fulfill one's duty until the end.

If we have to deal with some unpleasant soul, let us not reject her, let us never abandon her. Let us always have the "sword of the spirit" in our mouths, to help her recover from her mistakes: let's not let things take their course, to protect our peace; let us fight constantly, even when there is no hope of winning the battle. What does success matter? God asks us not to stop in front of the efforts of the fight, not to lose courage and to say: "It keeps getting worse! There is nothing more to be done, I will give up." Oh, that is cowardice; we must fulfill our duty until the end.

(Thérèse of Lisieux, Last Conversations, April 6, 1897)