God’s Knowledge:
In thinking about God’s knowledge theologically it was customary for many years, until and including the Reformation, to distinguish between God’s necessary knowledge and His free knowledge. The distinction is obvious and natural. God’s necessary knowledge includes several kinds of truths. It is the knowledge of matters such as the truths of mathematics (for example, 2+2=4). It is also the knowledge of truths such as the whole is greater than the part and no circle can be a square. God’s necessary knowledge also includes His knowledge of all possibilities, such as possible people, the possible lives they could lead, and the whole range of possible worlds. These are known to God immediately and intuitively.
God’s free knowledge, on the other hand, is His knowledge of His decree (of that which, in His wisdom, God freely and unchangeably ordained to come to pass). That which God decrees is obviously a subset of all the possibilities that are known to Him. His decree also has its source solely in His mind and will.
The Council 