A. Discursive knowledge arises from an imperfection in intellectual nature. For that which is known through another is less known than what is known through itself; nor is the nature of the knower sufficient for knowing that which is known through another without that through which it is made known. But in discursive knowledge something is made known through another, whereas that which is known intellectually is known through itself, and the nature of the knower is able to know it without an external means. Hence, it is manifest that reason is a certain defective intellect. — SCG I.57.9
B. Please don't wear red tonight.
C. The contingent is opposed to the certitude of knowledge only so far as it is future, not so far as it is present. For when the contingent is future, it can not-be. Thus, the knowledge of one conjecturing that it will be can be mistaken: it will be mistaken if what he conjectures as future will not take place. But in so far as the contingent is present, in that time it cannot not-be. It can not-be in the future, but this affects the contingent not so far as it is present but so far as it is future. Thus, nothing is lost to the certitude of sense when someone sees a man running, even though this judgment is contingent. All knowledge, therefore, that bears on something contingent as present can be certain. But the vision of the divine intellect from all eternity is directed to each of the things that take place in the course of time, in so far as it is present, as shown above. It remains, therefore, that nothing prevents God from having from all eternity an infallible knowledge of contingents. — SCG I.67.2