Harry Potter and the Deathly Hallows
How we cite our quotes:
Terror washed over him as he lay on the floor, with that funeral drum pounding inside him. Would it hurt to die? All those times he had thought that it was about to happen and escaped, he had never really thought of the thing itself: His will to live had always been so much stronger than his fear of death. Yet it did not occur to him now to try and escape, to outrun Voldemort. It was over, he knew it, and all that was left was the thing itself: dying. (34.3)
Faced with inevitable death, Harry has to think about the experience of it for the first time – and it's scary. Even in his most dangerous moments, death has never seemed so real as now, when it's the only possible choice.
Slowly, very slowly, he sat up and as he did so he felt more alive and more aware of his own living body than ever before. Why had he never appreciated what a miracle he was, brain and nerve and bounding heart? It would all be gone… or at least, he would be gone from it. (34.5)
The awareness of mortality makes Harry all the more aware of his own life – for, after all, he's taken it for granted until now, when it's all going to be taken away.
He had no strength left for a Patronus. He could no longer control his own trembling. It was not, after all, so easy to die. Every second he breathed, the smell of the grass, the cool air on his face, was so precious: To think that people had years and years, time to waste, so much time it dragged, and he was clinging to each second. At the same time he thought he would not be able to go on, and knew that he must. (34.36)
As he's about to go to his death, Harry longs only to live – and who wouldn't? Even though he's doing the right thing for the world, imagine being in his situation. When it comes down to your own life, even the best reasons couldn't possibly seem good enough to end it.