" In a way that he did not entirely understand, their sparring seemed to have become something more than just a test of arms; it had become a test of who he was: of his character, of his strength, and of his resilience. Nor was it Glaedr who was testing him, or so he felt, but rather Arya. It was as if she wanted something from him, as if she wanted him to prove…what, he knew not, but he was determined to acquit himself as well as he could. However long she was willing to keep sparring, so too was he, no matter how much it hurt.
A drop of sweat rolled into his left eye. He blinked, and Arya lunged at him, shouting.
Once more they engaged in their deadly dance, and once more they fought to a standstill. Fatigue made them clumsy, yet they moved together with a rough harmony that prevented either from gaining victory.
Eventually, they ended up standing face to face, their swords locked at the hilts, pushing at each other with what little remained of their strength.
Then, as they stood there, struggling back and forth without avail, Eragon said in a low, fierce voice, “I…see…you.”
A bright spark appeared in Arya’s eyes, then vanished just as quickly. "

― Christopher Paolini , Inheritance (The Inheritance Cycle, #4)