How do you teach the Old?

I've been told if your children's curriculum says the moral of the
David and Goliath story is that little people can be used by God too,
then you should throw out your books and look into new curriculum.

But why?

I'm reading a book right now which promises to make enough sense out
of the Old Testament to be able to understand just how it should be
taught. It doesn't seem full of the practical application that the New
Testament does seemingly merely because of its nature being much more
historical and also containing the wisdom and lament literature.

Anyhow. I'll keep you posted on what I learn. I guess the point is
that we have to remember the Old Testament through the light of the
New Testament. Everything that happened in the old seems to at some
level point to the new.... we'll see.