A common objection to belief in the God of the Bible is that a good, kind, and loving deity would never command the wholesale slaughter of nations. Even Christians have a hard time stomaching such a thought, and many avoid reading those difficult Old Testament passages that make us squeamish. Instead, we quickly jump to the enemy-loving, forgiving Jesus of the New Testament. And yet, the question doesn't go away. Did God really command genocide? Is the command to "utterly destroy" morally unjustifiable? Is it literal? Are the issues more complex and nuanced than we realize?

In the...