From Albert Camus’ “The Plague”, Part IV: a conversation between priest(Paneloux) and doctor(Rieux), shortly after witnessing the death of a child:

He heard a voice behind him. “Why was there that anger in your voice just now? What we’d been seeing was as unbearable to me as it was to you.”
Rieux turned toward Paneloux.
“I know. I’m sorry. But weariness is a kind of madness. And there are times when the only feeling I have is one of mad revolt.”
“I understand,”Paneloux said in a low voice. “That sort of thing is revolting because it passes our human understanding. But perhaps we should love what we cannot understand.”
Rieux straightened up slowly. He gazed at Paneloux, summoning to his gaze all the strength and fervor he could muster against his weariness. Then he shook his head.
“No, Father. I’ve a very different idea of love. And until my dying day I shall refuse to love a scheme of things in which children are put to torture.”
A shade of disquietude crossed the priest’s face. “Ah, Doctor,” he said sadly, “I’ve just realized what is meant by ‘grace.'”
Rieux had sunk back again on the bench. His lassitude had returned and from its depths he spoke, more gently:
“It’s something I haven’t got; that I know. But I’d rather not discuss that with you. We’re working side by side for something that unites us–beyond blasphemy and prayers. And it’s the only thing that matters.”
Paneloux sat down beside Rieux. It was obvious that he was deeply moved.
“Yes, yes,” he said, “you, too, are working for man’s salvation.”
Rieux tried to smile.
“Salvation’s much too big a word for me. I don’t aim so high. I’m concerned with man’s health; and for me his health comes first.”
Paneloux seemed to hesitate. “Doctor–” he began, then fell silent. Down his face, too, sweat was trickling. Murmuring: “Good-by for the present,” he rose. His eyes were moist. When he turned to go, Rieux, who had seemed lost in thought, suddenly rose and took a step toward him.
“Again, please forgive me. I can promise there won’t be another outburst of that kind.”
Paneloux held out his hand, saying regretfully:
“And yet–I haven’t convinced you!”
“What does it matter? What I hate is death and disease, as you well know. And whether you wish it or not, we’re allies, facing them and fighting them together.” Rieux was still holding Paneloux’s hand. “So you see”–but he refrained from meeting the priest’s eyes–“God Himself can’t part us now.”