There it is, as my late father-in-law would say, “in a nutshell.” He meant, of course, the “heart of the matter,” the “core” of the book of James, and you will find it in James 4:4.
“You adulterous people, don’t you know that friendship with the world is hatred toward God? Anyone who chooses to be a friend of the world becomes an enemy of God.”
Throughout the book, James addresses this “fence straddling” mentality. You know the kind: on the one hand, we want to be on the side of God. On the other, we love what we see in the world and long to be home here. To afraid to give up one for the other, we find ourselves on the fence, with a foot in both worlds and never really committing to either.
You see it a lot here: There’s the “doubter” who is tossed to and fro like a wave of the sea. There’s the “forgetter,” who sees himself in God’s mirror but once away, forgets what he has seen. There are the “segregationists” who are delighted to have rich and poor alike worship with them, but give preference to the rich who, by the way, make their lives miserable.
I find it significant James addresses his readers as an “adulterous” generation. These are Christians remember, believers in the Lord Jesus Christ. James issues an altar call, for his brethren to get off the fence and once again present themselves as living sacrifices to God; to wash and purify themselves and submit to God.
Don’t miss it: God is responsible for cleansing the sinner; but the sinner is responsible for staying clean.