When S.G. De Graaf wrote his four-volume series, Promise and Deliverance, he showed educators how to teach Bible stories from a redemptive-historical perspective. Rather than turning Bible stories into moralistic tales, De Graaf taught us how all the Bible shows God revealing himself as the God of the covenant, who is working out His redemptive plan for humanity and all of creation.
The 80 workbooks written by Harvey De Groot are meant to supplement De Graaf's work. They are divided by volume and level number: 20 volumes with four levels per volume. Workbook lessons are written at four levels so that families with students in various grades can study the same Bible stories during the week in preparation for their classes on Sunday. Prior to class, the Sunday School teacher should study the lesson in De Graaf's book. The teacher and students can go through the workbook during class.
The levels are divided according to the following grades: