4 You adulterous people,don’t you know that friendship with the world means enmity against God? Therefore, anyone who chooses to be a friend of the world becomes an enemy of God. 5 Or do you think Scripture says without reason that he jealously longs for the spirit he has caused to dwell in us? 6 But he gives us more grace. That is why Scripture says: “God opposes the proud but shows favor to the humble.”
When the early Christians chose to indulge in their pleasures instead of serving God, James says they are choosing the world over Him. How? Jesus says, "You cannot serve two masters. Either you will grow to love the one, and/or hate the other. You cannot serve both God and money." Adultery seems like a strange word to use in this situation. But what is adultery? It is choosing to not be faithful to the one you have given yourself to, and giving yourself to someone else.
So then it makes sense that James would talk about our relationship with God, and how he jealously longs for the Spirit he has caused to dwell within us. When someone's spouse commits adultery, they feel jilted and betrayed. God loves us just like that, and became part of us when His Spirit dwelt in us through Christ. That is the sense in which we are one with God and dwell with Him. So when we choose turn to the world to get our needs met (James calls this "friendship with the world"), God sees this as turning from Him and His love. The verse calls this "enmity" against God. The word means, "a hostility, or deep seated ill will toward someone." You see this is no tiny matter.
But then James says, "But God gives us more grace." Meaning even when we spurn God for the world, God keeps coming after us. God never gives up on us, though we might be tempted to give up on him. It is not as if God wants us to hate the world. God calls us out into the world to bring it closer to Him. He wants us to be His salt and light in the world. He wants us to be "in" the world, but not "of" the world. Why? Because we are the people He has called out of the world to give praise to His name. He is our God and we are the sheep of His pasture. He has left in the world so that He might be able to communicate His grace toward the world through us. Remember God so loved the WORLD!
So today, remember who your friends are, and how God has chosen you to be His friend forever!