This is a part of the Calvin's Institutes summary series post #4.
All human beings are given some knowledge of God, yet all such knowledge is corrupted. Some turned to lesser gods of their own imagination (which are no gods at all) and some consciously rejected and refused to seek the true God. Still others think of God only when difficulties in life arise. All these point to the reality of God and the knowledge of God in all human beings, yet, in their own stubbornness, they have all turned away from that knowledge.