What leads to [the unending] quarrels and conflicts among you? Do they not come from your [hedonistic] desires that wage war in your [bodily] members [fighting for control over you]? You are jealous and covet [what others have] and your lust goes unfulfilled; so you murder. You are envious and cannot obtain [the object of your envy]; so you fight and battle. You do not have because you do not ask [it of God]. You ask [God for something] and do not receive it, because you ask with wrong motives [out of selfishness or with an unrighteous agenda], so that [when you get what you want] you may spend it on your [hedonistic] desires.
Each person lives in submission to someone. We have the choice to submit to and serve ourselves, or to submit to and serve God. In these verses, James is speaking to believers who either have forgotten or never understood that following Jesus requires the denial of self. When self-denial is not practiced and people live to serve their ungodly desires, their lust and their selfishness, the Church cannot have peace. As we see here, this kind of behavior leads to endless conflict, but that is secondary to the foundational relationship that suffers as a result.
When our selfish desires drive what we pursue, and in turn drive our prayers, our prayers go unanswered. We pray outside the will of God, and He does not respond. What results is an interruption of the constant communion we are commanded to have with the Father, praying without ceasing in all things [1 Thes. 5:17]. Our spiritual lifeline has been severed. How can we expect God to guide us when we have decided to live outside his will and focus on us instead of him?
When we make ourselves the focus, our relationships with both God and the brethren suffer. This is nothing to be taken lightly. Envy, covetousness and lust that can lead to war and murder are real pitfalls for us if we are not vigilant to be focused on God first. Above all, we should fear the loss of our communion with God, as we cannot live within his will otherwise. Father, remove from us all desire to serve ourselves, and replace it with the self-denial that You require for us to live within your will.