"Even God Cannot Change The Past"

Context: Aristotle, in discussing morality, says that in all moral states there is some object which the rational man keeps in view in intensifying or relaxing his activity: this object should be the mean, or the state between two extremes. The intellect, Aristotle says, is divided between the speculative intellect and practical intellect; the function of the speculative intellect is to apprehend truth in conformity with right reason. Thus moral purpose is the origin of action, which implies reason. It then follows that moral purpose is intellectual desire, and it is this intellectual desire which makes a man. Anything that is desired must be something in the future, as it is impossible to desire things in the past. Aristotle explains it thus:

But nothing which is done and past can be the object of moral choice; for instance, no man chooses to have sacked Troy; because, in fact, no one ever deliberates about what is past but only about that which is future and which may therefore be influenced, whereas what has been cannot not have been: and so Agathon is right in saying,
Even God cannot change the past.