If you're looking for ideas for what to use besides the obvious choice being the Bible, then you can check out my favorite resources and ideas on this post. I've listed lots of our favorite picture books, music resources, and scripture memory resources. I love using picture books to teach all kinds of subjects. There are some wonderfully illustrated children's books that parents and teachers can use to teach about the Bible.
This post also includes links for ideas of what to use with older students.