Knowledge is sometimes superfluous: when we need it, we have it not.

In truth, opinion may be taken for understanding; understanding cannot be taken for opinion. How so? Surely because opinion may be deceived; understanding cannot be. If it could, it would not be understanding but opinion. For true understanding has not only certain truth, but the knowledge of truth.

He has the scientific knowledge, and I have the political knowledge,

How is it that in Ireland, where they never had any knowledge of God but, always, until now, cherished idols and unclean things, they are lately become a people of the Lord, and are called children of God; the sons of. the Irish and the daughters of the chieftains are to be seen as monks and virgins of Christ.

The superfluous, a very necessary thing

God will not suffer man to have a knowledge of things to come; for if he had prescience of his prosperity, he would be careless; and if understanding of his adversity, he would be despairing and senseless