Theists, tell me, an atheist, why your God has neglected to show himself to me?

[John V]

Meh, I suppose, and I appreciate that some christers believe that the failure in that lay with the invading forces faith - that god could have gotten rid of those chariots...but didn't.  God would say that, though, wouldn't he?  

I, like this legendary army of hebrews, am skeptical of god's empty promises.

There you go. If God intends to use his people to accomplish a purpose and those people, lacking faith, don't show up, then the purpose might not be accomplished.

Before even getting this far, you could say that God couldn't drive anyone out because they were too powerful. See Numbers 13-14. God was able, but he waited for the next generation.

We see the same thing with Jesus in his hometown. 

Mark 6
5 Now He could do no mighty work there, except that He laid His hands on a few sick people and healed them. 6 And He marveled because of their unbelief. 

Jesus performed mighty works elsewhere. Even there he healed a few sick people. Why couldn't he do a mighty work there? Elsewhere, people came to Jesus with people needing a "mighty work," and he performed mighty works. Note that people have to have faith to bother taking someone to Jesus. Since people in his home town didn't have faith that he could perform mighty works, they didn't bring people requiring them, and so the works weren't performed.