" And if it means the difference between gaining the shawl or losing it forever?” “Giving an oath like that would be foolish,” Nynaeve said. “I could find myself in a situation where people would die if I didn’t use it. Light! I’ll be fighting in the Last Battle alongside Rand. What if I were to get to Shayol Ghul and discover that, without balefire, I could not help the Dragon stop the Dark One? Would you have me choose between a foolish oath and the fate of the world? "

― Robert Jordan , Towers of Midnight (The Wheel of Time, #13)