Locke can't cross the ash, sends Claire into the temple

Outside the temple, Locke and Claire are standing at the line of ash. Claire asks Locke why he can't send Sawyer or Jin inside or do it himself. Locke says that he would do it himself if he could. Claire makes him swear to her that she'll get what he promised her which is getting Aaron back. Locke says "I always do what I say" and that he's only going to hurt the people inside who don't listen.