The fundamental error of the atheist is his imagination of autonomy, that his unbelief makes him free of the sovereignty and judgment of God. This is, in fact, Satan's promise to Adam and Eve in the garden (Genesis 3:5). What is sad, though, is the efforts of so many professing Christians to hold on to the same error. Of course, we immediately think of nominal or liberal Christians, who claim the name of Christ, but have zero spiritual commitment. However, I think even of those evangelicals of the Pelagian and Arminian end of the
To my mind, that is worse than the unbelief of the atheist. The atheist makes no pretense of honoring God's Word. The Arminian, however, pretends exactly that, while still holding an essentially-atheist view of the sovereignty of God.
The Arminian has to hold to the incompatible precepts of autonomous free will and the biblical description of God's rule: "A man’s steps are from the Lord; how then can man understand his way?" (Proverbs 20:24).
The biblical worldview, that of the Calvinist, holds to free will, too, but in a far different way from the Arminian. Properly speaking, the will is free, in that it chooses according to its own intent, without coercion. However, the will is not free in the sense that it is able to choose any random thing. Rather, it chooses freely according to its nature. The will is fallen, sinful, and, therefore, freely chooses to act wickedly (Isaiah 64:6, Romans 3:10-12, 23).
As the writer of Proverbs asserts, it is God who is sovereign, not the will of man. Therefore, man always acts, freely choosing to do so, according to his sinful purposes, but also according to the predetermination of God, "who works all things according to the counsel of His will" (Ephesians 1:11).