My thanks to Paul Helm for pointing me this section on God's exhaustive foreknowledge in Augustine's City of God (Book Five, Chapter Nine, "Concerning the foreknowledge of God and the free will of man, in opposition to the definition of Cicero")
To confess that God exists, and at the same time to deny that He has foreknowledge of future things, is the most manifest folly
What is it, then, that Cicero feared in the prescience of future things? Doubtless it was this,—that if all future things have been foreknown, they will happen in the order in which they have been foreknown; and if they come to pass in this order, there is a certain order of things foreknown by God; and if a certain order of things, then a certain order of causes, for nothing can happen which is not preceded by some efficient cause.
But if there is a certain order of causes according to which everything happens which does happen, then by fate, says he, all things happen which do happen. But if this be so, then is there nothing in our own power, and there is no such thing as freedom of will; and if we grant that, says he, the whole economy of human life is subverted.
In vain are laws enacted. In vain are reproaches, praises, chidings, exhortations had recourse to; and there is no justice whatever in the appointment of rewards for the good, and punishments for the wicked. And that consequences so disgraceful, and absurd, and pernicious to humanity may not follow, Cicero chooses to reject the foreknowledge of future things, and shuts up the religious mind to this alternative, to make choice between two things, either that something is in our own power, or that there is foreknowledge,—both of which cannot be true; but if the one is affirmed, the other is thereby denied.
He therefore, like a truly great and wise man, and one who consulted very much and very skillfully for the good of humanity, of those two chose the freedom of the will, to confirm which he denied the foreknowledge of future things; and thus, wishing to make men free he makes them sacrilegious. But the religious mind chooses both, confesses both, and maintains both by the faith of piety.
Now, against the sacrilegious and impious darings of reason, we assert both that God knows all things before they come to pass, and that we do by our free will whatsoever we know and feel to be done by us only because we will it. But that all things come to pass by fate, we do not say; nay we affirm that nothing comes to pass by fate; for we demonstrate that the name of fate, as it is wont to be used by those who speak of fate, meaning thereby the position of the stars at the time of each one’s conception or birth, is an unmeaning word, for astrology itself is a delusion. But an order of causes in which the highest efficiency is attributed to the will of God...
Cicero, then, contends with those who call this order of causes fatal, or rather designate this order itself by the name of fate; to which we have an abhorrence, especially on account of the word, which men have become accustomed to understand as meaning what is not true. But, whereas he denies that the order of all causes is most certain, and perfectly clear to the prescience of God, we detest his opinion more than the Stoics do.
For he either denies that God exists,—which, indeed, in an assumed personage, he has labored to do, in his book De Natura Deorum,—or if he confesses that He exists, but denies that He is prescient of future things, what is that but just “the fool saying in his heart there is no God?” For one who is not prescient of all future things is not God.