Madness
Madness in Scripture refers to several distinct phenomena: genuine mental illness, divinely inflicted confusion as a covenant curse, and behavior that is morally irrational from God's perspective. As a covenant curse, loss of sanity is listed among the penalties for disobedience in Deuteronomy 28:28, 34: "The LORD will afflict you with madness and blindness and confusion of mind... you shall be driven mad by the sight that your eyes shall see." In Zechariah 12:4 God promises to strike the horses of Israel's enemies with madness as an act of deliverance.
The Old Testament records cases of behavior resembling mental disturbance: Saul's torment by an evil spirit (1 Samuel 16:14–23), David's feigned madness before Achish of Gath (1 Samuel 21:13–15), and Nebuchadnezzar's years of animal-like derangement (Daniel 4:33). Ecclesiastes uses the Hebrew holelut (madness, folly) for the vanity of pursuing pleasure and wisdom without God (Ecclesiastes 1:17; 2:12). In the New Testament, opponents of Jesus and Paul attribute their behavior to madness (John 10:20; Acts 26:24–25), a charge both reject by appealing to evident reality and truth.