Anyone who deliberately chooses to love the world is thereby making himself God’s enemy. Do you think what the scriptures have to say about this is a mere formality? (James 4:4b,5a)
Which begs the question: What would that latter question have meant to James' original readers, given that the New Testament didn't, at this time, exist? Well, consider some of the Old Testament context to which, perhaps, James was pointing their minds:
That's the War He's still fighting in and through us today. Let us march out under His orders only.