Selfishness. When it really comes down to it, sin is a desire to please self over a desire to please God. Read James 4:1.
What is the source of quarrels and conflicts among you? Is not the source your pleasures that wage war in your members?
James 4:1 NASB
As James is moving from understanding Godly wisdom, he now is going to review things we should be avoiding. Why? If we truly are living each day with Godly wisdom then we would be wise to avoid these things because they cause arguments and anger. James knows that every argument can come down to selfishness instead of being focused on God.
Do we lose track of our desire to see God’s will done? When that happens, it naturally gets replaced by our desire to see our will done. If we are not diligent and intentional about seeking God’s then we will get caught up in the desire to seek our own.
Whose will are you seeking? If there are lots of arguments and fighting among the believers around you, then you can guess that it’s not God’s. Keep your focus on God’s will.