"That is a point which you and I can agree on," he says. "I realize fully that she is a far stronger mage than I, and her other abilities lend themselves in her favor...she could easily take care of herself, against most. But regardless, I have sworn to your sister that so long as I am able to aid her in defense, I would seek to keep harm from coming to her. It is just what is right."

He might be a bit 'old-fashioned' in that regard, but it is what it is.