‘I shall decide what I do. If you say my work is fighting, or healing, or exploring, or whatever you might say, I’ll alway be thinking about it, and if I do end up doing that I’ll be resentful because it’ll feel as if I didn’t have a choice, and if I don’t do it, I’ll feel guilty because I should. Whatever I do, i will choose it, no one else.’
'Then you have already taken the first steps towards wisdom.’
—  The Amber Spyglass

As the boy and the girl and the two daemons watched her approach, Xaphania spread her wings wider and glided down to the sand. Will, for all the time he’d spent in the company of Balthamos, wasn’t prepared for the strangeness of this encounter. He and Lyra held each other’s hands tightly as the angel came toward them, with the light of another world shining on her. She was unclothed, but that meant nothing. What clothes could an angel wear anyway? Lyra thought. It was impossible to tell if she was old or young, but her expression was austere and compassionate, and both Will and Lyra felt as if she knew them to their hearts.

“Will,” she said, “I have come to ask your help.”

“My help? How can I help you?”

“I want you to show me how to close the openings that the knife makes.”

Will swallowed. “I’ll show you,” he said, “and in return, can you help us?”

“Not in the way you want. I can see what you’ve been talking about. Your sorrow has left traces in the air. This is no comfort, but believe me, every single being who knows of your dilemma wishes things could be otherwise; but there are fates that even the most powerful have to submit to. There is nothing I can do to help you change the way things are.”

[…] Will felt a great wave of rage and despair moving outward from a place deep within him, as if his mind were an ocean that some profound convulsion had disturbed. All his life he’d been alone, and now he must be alone again, and this infinitely precious blessing that had come to him must be taken away almost at once. He felt the wave build higher and steeper to darken the sky, he felt the crest tremble and begin to spill, he felt the great mass crashing down with the whole weight of the ocean behind it against the iron-bound coast of what had to be. And he found himself gasping and shaking and crying aloud with more anger and pain than he had ever felt in his life, and he found Lyra just as helpless in his arms. But as the wave expended its force and the waters withdrew, the bleak rocks remained; there was no arguing with fate; neither his despair nor Lyra’s had moved them a single inch.

How long his rage lasted, he had no idea. But eventually it had to subside, and the ocean was a little calmer after the convulsion. The waters were still agitated, and perhaps they would never be truly calm again, but the great force had gone.

They turned to the angel and saw she had understood, and that she felt as sorrowful as they did. But she could see farther than they could, and there was a calm hope in her expression, too.

- Philip Pullman, His Dark Materials (The Amber Spyglass)