Classical Sunday School suggests three different texts for teaching Bible stories: the Bible, Hurlbut's Story of the Bible, and The Child's Story Bible by Catherine F. Vos.
Whenever possible, we recommend that you teach directly from the Bible. Narrative books like Genesis, I & II Samuel, Mark, and Acts are easy for even young children to understand. The books of poetry like Psalms and Proverbs are honey for a child's soul.
But certain portions of the Bible that are full of obscure historical references or laden with rich doctrine are better taught through excellent summaries when students are young.
Hurlbut's Story of the Bible was the best-selling Sunday School curriculum in America in the first part of the 20th century. Hurlbut uses a grandfatherly tone as he summarizes the sweep of the Scriptures. He includes geographical references and does an excellent job of presenting the Bible as a unified whole.
Mrs. Vos's superb book is perhaps better for younger children (ages 3-7). In her very sweet voice she connects her stories over and over again to the winsome story of redemption woven throughout the Scriptures.