Find me a quote, Harry Potter fans!?

In chapter 19 The Silver Doe when Harry sees the sword of Gryffindor under the ice and thinks..."Their daring, nerve and chivalry set Gryffindors apart". Where 'chivalry' entered into this, he thought ruefully, he was not entirely sure, unless it counted as chivalrous that he was not calling for Hermione to do in his stead.