Desire at War and Friendship with the World
James asks where wars and fights come from and answers by tracing them inward to pleasures and desires at war within the members. Desire becomes violence; failed desire becomes conflict; even prayer can be twisted into a tool for consumption. James then uses covenant-marriage language: friendship with the world is enmity with God, so divided loyalty is spiritual adultery.
Where this fits in the story: Israel’s prophets repeatedly describe idolatry and covenant infidelity as adultery. James applies that prophetic category to worldly allegiance. The letter’s earlier “double-minded” person now appears as a divided lover.