Why Did God Command Killing in the Old Testament—and Why Is It Not for Christians Today? The Old Testament records moments when God commanded Israel to kill: the conquest of Canaan (Deuteronomy 20:16–18), the destruction of idolatrous nations (1 Samuel 15:3), and capital punishments within Israel’s law. Many readers struggle with these texts, especially when Jesus teaches “Love your enemies” (Matthew 5:44 NASB).