The theological heart of Let There Be Light is an explanation of tsimtsum, a kabbalistic teaching of the 16th-century rabbi Isaac Luria. Before God could create the world, Finck explains, she had to ...

and "when?" Suppose you were to ask, "When did God create light?" Was it the first day of creation as Genesis 1:5 indicates? Or was it the fourth day of creation as Genesis 1:14-19 reveals?