In a grassy square dotted with Adirondack chairs that lies at the heart of the Pentagon, evangelist Franklin Graham delivered a special sermon in December at the request of Defense Secretary Pete Hegseth. “We know that God loves,” Mr. Graham said. Then, he took a turn. “Did you know that God also hates?” he asked the dressed-up children and troops attending. “Do you know that God is also a god of war?” Mr. Graham then told a story about God taking revenge on ancient Israel’s enemies. “Kill them, both man, woman, infant, nursing child, ox, sheep, camel, and donkey,” Mr. Graham said, quoting the Bible. For those who don’t believe in a vengeful God, “Well,” he warned, “you’d better believe in him.” Why We Wrote This Public prayer for troops has long been a part of America’s history. But Defense Secretary Pete Hegseth’s rhetoric is raising concerns about the impact that Christian nationalist ideas are having on military unity and religious freedom. Secretary Hegseth thanked Mr. Graham for his “bold” message.…