In order for any recollection and confession to take place, Augustine argues, a consideration of time and memory must be taken. In Book 3, for example, Augustine works through a philosophy about history that allows for a law to be just in one time period and unjust in another. This idea accommodates the fact, for instance, that righteous actions from the Old Testament might not be righteous later in history. For Augustine, justice has her temporal reasons, and the context of time plays a role in every situation.
In Book 4, Augustine reflects on the memory of a friend who has passed away, and such thoughts trigger a long philosophy about time and perception. He explores the meaning of sorrow and the depth of loss. Before Augustine knew god, he had great difficulty making his peace with or even accepting death, and time played tricks on his mind. He acknowledges that time seems curious and later devotes entire books to exploring the concept.
In Book 11, Augustine dives deeper into the question of time. From many aspects, he explores the intersection of humans experiencing time and wonders what time means as it relates to god. In general, he believes that god is the eternal present. Only humans think of experience in terms of past and future. He asks questions, forms theories, and continues to praise the lord as he writes about what he calls the temporal medium.
Finally in Book 11 Augustine tries to imagine what time means to god and here postulates that god exists in an eternal present moment that exists outside the human boundaries of time. He writes about the past and future, about speaking a line of verse slowly and quickly, and about how time might be defined by the movements of the sun, moon, and stars.