Again Paul used Old Testament quotations to give added authority to his statements (cf. 1 Corinthians 1:19; 1 Corinthians 1:31; 1 Corinthians 2:9; 1 Corinthians 2:16). Here he referred to Job 5:13 and Psalm 94:11. The best wisdom the natural man can produce is foolishness compared with the wisdom God has revealed in His Word. Unbelieving humanity cannot avoid God"s judgment through its own rationalizing. The reasoning of the wise of this world is useless regarding the most important issues of life. In 1 Corinthians 1:18-25 Paul had said that the wisdom of God, namely, Christ crucified, is foolishness to the world. Here he made the same point in reverse: the wisdom of the world is foolishness in God"s sight. Thus these statements form bookends for this section of text (an inclusio). [source][source][source]