JOel Beeke and Paul Smalley on the Foolishness of Athiesm

Beeke and Smalley write,

God's revelation of himself exposes the foolishness of atheism. "The fool hath said in his heart, There is no God" (Ps. 14:1). The word translated as "fool" (nabal) refers not to a lack of intellectual ability, but to a lack of moral sense as exhibited in contempt for God and his people (74:18, 22). In the Bible, a fool is not someone who lacks intelligence, but one who abuses his intelligence, as Stephen Charnock said. This denial of God may not be an open stance of atheism, but a practical stance of "his heart." The root of moral foolishness is a blindness to God's glory so that the fool does not fear God (94:6-11; cf. 36:1-2; 92:5-8). The thought "There is no God" might not entail an absolute denial of God's existence, but at a minimum it involves a practical denial of God's lordship in one's situation. Sinners soothe themselves with Satan's lie that God is ignorant of or unwilling to judge their iniquities. They convince themselves that the Lord cannot help them in their needs, and they turn instead to false gods that can do nothing (2 Kings 1:3, 6, 16). In their refusal to honor God, their hearts are plunged into spiritual darkness and become enthralled with idolatry and immorality (Rom. 1:21-25). This culpable ignorance of God characterizes the nations (Eph. 4:17-18). John Frame says, "A large percentage of people today would say that they believe in God, but they rarely give him a thought, and they routinely make their decisions as if he didn't exist." That, too, is foolish.

Beeke, Joel and Paul Smalley. Reformed Systematic Theology. vol. 1. Revelation and God. Wheaton, IL: Crossway. 2019, pg. 507. (emphasis mine)