Calvinism and Free Will, Chap. 3, Does God have a free will?
Answering this question requires an understanding of how choice is exercised.
God is self-existent, the First Cause. His nature is defined by certain characteristics, but they had no cause. God does indeed have a will which is subject to no other, but it cannot violate his nature, the essence of his being. So in one sense his will is free in that it is not affected by anything outside himself, yet in another it is not free in that it is limited by his character. God’s character determines the limitations of his will, or to put it another way, God’s will is accountable to his nature. So will and nature are two separate things. We can think of nature as a kind of fence around the will, a limiting factor that nonetheless allows autonomy within its parameters.
But God’s will is not caused by his nature. God willed to create the universe, but his nature did not compel or force him to do so. There is nothing in God’s character that forced him to act. But if every choice must have a cause (otherwise choice would be impossible), then what caused God to create the universe?
There must be two types of causation: event and agent. Event causation would be where one event causes another, and agent causation would be primary– in the nature of the agent. In other words, there is no event required to cause a primary choice– an act of will. God acts independently from, but limited by, his nature. He is an agent, a sentient being, a primary cause.