The city breathing, burning, living the life thy had preserved. Ten million lives and more. If something should happen to all that life - how terrible! Nita gulped for control as she remembered Fred's word of just this morning, an eternity ago. And this was what being a wizard was about. Keeping terrible things from happening, even when it hurts. Not just power, or control of what ordinary people couldn't control, or delight in being able to make strange things happen. Those were the side effects - not the reason, the purpose.
"So You Want To Be a Wizard (Young Wizards, Book 1)". Book by Diane Duane, 1983.