The length of a day is relevant for Augustine because Genesis describes God’s creation of the universe as taking place over a sequence of days. His conjectures about what constitutes a “day” are difficult to follow, but the point readers shouldn’t miss is that Augustine ultimately finds time impossible to define—yet he still finds the question worth prayerfully exploring, because it touches on God’s being and humans’ inescapable dependence on God. Readers should also note Augustine’s reference to a story in the book of Joshua, in which God caused the sun to stand still in order to let the Israelites finish and win a battle against the Amorites. His use of this example demonstrates that even though Augustine criticized aspects of Manichean interpretation as being excessively literal, that doesn’t mean his own interpretation was solely metaphorical.