Joan King ("Faith Gone Wrong Can Lead to War," June 16) is right about blood flowing freely in the Old Testament. Of course there's much more as well: truth and wisdom; great poetry; the thoughtful puzzling of men and women over God's will and ways; stories about the Israelites and their relationship to God, one another, and the peoples around them.

But, yes, there is blood, sometimes from a surprising direction: Among my favorites of the 150 ancient Hebrew hymns-praises-meditations known as "The Psalms" is 137, a lyrical lament of an exiled people in the bondage of slavery, yearning for home and freedom.

It begins: "Beside the streams of Babylon / we sat and wept / at the memory of Zion, / leaving our harps / hanging on the poplars there. / For we had been asked / to sing to our captors, / to entertain those who had carried us off."

And so it goes. But near the end Psalm 137 takes a horrific turn and closes with: "... a blessing on him who takes and dashes / your babies against the rock."

Who could even think of such barbarity, particularly after the lyrical longing of the opening?

In those ancient days many not only thought it, but did it. Killing an enemy's children, especially boys, was common. It meant a people's own sons would have fewer men to battle when they grew up; their daughters might have a better chance of avoiding slavery and other abominations.

Stoning was also a common punishment, and remains so in certain quarters. But the West, and much of the world, long ago left behind stoning, and other such barbarities. Jesus Christ was a force for this change — "Let he who is without sin cast the first stone" — and for a broader moral advance that set aside eye-for-an-eye vengeance, and called for love, mercy and forgiveness.

Yet, Ms. King sees a parallel between the violence of The Old Testament and that in the Quran. "When I hear Christians attack Islam because parts of the Quran call for Holy War," she writes, "I wonder: Do these people ever read their own scripture?"

Her parallel isn't a parallel at all. The test isn't whether the scriptures contain violence; the test is the actions of those who read and study those scriptures. Further, reading the Quran is not what prompted so many people to believe that Islam contained a violent strain; it was widespread killing and violent pronouncements by radical Jihadists. (Most Christians and others distinguish between the practices of Islam in general and those of radical Jihad.)

There was growing discussion and speculation about these violent strains before 9-11. The crashing of airliners into three buildings, killing 3,000 people in one morning, increased such talk considerably here in America.

Ms. King is often troubled about possible violence by Christians. And some few Christians, a handful of loners, have killed in the name of God. But Christians are obviously not waging a concerted Holy War in America, or anywhere else, like that being waged by radical Jihadists around the world.

And there is a larger point: As Ms. King frets about the dangers of faith, particularly here in America, she seems blind to one of the 20th century's primary lessons: In large swathes of the world, political ideology and ambition have long been more powerful triggers for war than has religion. Despots like Hitler, Stalin, Mao, Pol Pot and Saddam Hussein collectively killed 60 to 100 million.

Even as Ms. King frets about the threat posed by Christians here, a despot in North Korea is "weaponizing" plutonium. On the Fourth of July, as he did on Memorial Day, he sent us a clear message, launching seven missiles this time.

A despot in Iran moves to have his finger on the trigger. Japan could be targeted by North Korea. Israel could be hit by Iran; Israel might strike Iran first. Radical Jihadists routinely target civilians in night clubs and marketplaces around the world.

Yet Ms. King, ever vigilant, would have us parse violence in The Old Testament.

Tack Cornelius is a writer living in Gainesville and an occasional contributor.