Reductio a.d. Absurdum

Then Peter answered: "You have presented us with a matter that can easily be answered. However, listen, how God is ignorant of nothing, but even foreknows. But first answer me what I ask of you. He who wrote the Bible, and told how the world was made, and said that God does not foreknow, was he a man or not?" Then I said: "He was a man." Then Peter answered: "How, then, was it possible for him, being a man, to know assuredly how the world was made, and that God does not foreknow?"