In this section of James’ letter (James 4:1-6) he addresses relationships, recognizing that it’s in the context of our many relationships that our grasp of God’s grace, or the lack thereof, can be seen most clearly. The gospel teaches us that the principle cause of the relational breakdown we experience cannot be blamed on things outside of us, but has everything to do with the sin inside of us.
Therefore, the solution is not to look within ourselves (by doing more, trying harder, asserting “self”) but rather by continually looking to the once-and-for-all work of Jesus Christ on the cross which saves us and frees us to admit our pride; selfishness; and wrong-doing in the context of our relationships and humbly ask for God’s grace. Consequently then what restores relationships is believing the gospel – taking God at his word in places like Ephesians 1 and Colossians 1 – and receiving the truth and functionally believing that as Christians, we have EVERY SPIRITUAL BLESSING we could want, long for, crave and desire in Jesus Christ. When we don't believe this we fight and quarrel to get what we think we must have to feel safe, secure, significant and satisfied.
“Under every behavioral sin is the sin of idolatry and under every idol is disbelief in the gospel.”- Martin Luther
On the other hand, a person who KNOWS they already have everything they need, crave, long for and desire because they KNOW Jesus has secured it for them already, they can live a life of humility that's expressed from a "my life for you" posture. A person who lives a "my life for you" life will discover peace, freedom and find relational healing in their relationships because they'll be able to extend the forgiveness and grace that they've received vertically, horizontally to those around them, which will halt the fights and quarrels they used to experience!
Humility is the best answer to your relational strife. And humility will become a reality in your life when you receive Jesus words, “It is Finished” into new and deeper parts of your inner most being every moment of everyday. When we receive the reality that “It is Finished” into the rebellious regions of our unbelief, we will discover peace, security and radical freedom! We will begin to live our lives from a “my life for you” posture and life of humility.