In The Bronze Bow, why is Daniel hesitant to have Jesus heal Leah?
Most of Daniel's antipathy towards Jesus comes from the latter's pacifistic nature. Daniel is working towards revenge and war with the Romans, intending to drive them out of Israel and reclaim the land. In addition, he sees Jesus as healing people to no real gain; the world is violent and harmful to his own people, and he doesn't see how healing the sick helps anyone. He even wonders if Jesus would bother coming out to heal a poor person instead of a nobleman.
"Do you really think that would make the slightest difference to Jesus?"
"No. No, I guess it wouldn't. But somehow I wonder. It's the same as the lame man. It's not much of a world, is it?
(Speare, The Bronze Bow, Google Books)
His hesitancy reflects both his need to have control of a situation -- Daniel doesn't want things happening out of his ability to affect -- and from his resentment at the upper-class of society. Because he has spent his whole life resenting the Romans, who are of necessity treated better, he believes that change and healing can only come from within. He sees Jesus as an outsider, at least at first, and aside from his love of his sister, Daniel simply doesn't want her illness affecting his mission of revenge.