What causes quarrels and what causes fights among you? Is it not this, that your passions are at war within you? (James 4:1)

The desires in our heart manifest themselves through action.
The spirit war against the flesh inside us. We feel the urge to satisfy the lust of the flesh (our sinful nature). It could be anger, jealousy, resentment, lust, covetousness, or discontent.
On the other hand, we reason that we are God’s children. We should leave the path of sin and walk righteously.
Paul had this experience.
For I do not understand my own actions. For I do not do what I want, but I do the very thing I hate …  So now it is no longer I who do it, but sin that dwells within me. For I know that nothing good dwells in me, that is, in my flesh. For I have the desire to do what is right, but not the ability to carry it out. For I do not do the good I want, but the evil I do not want is what I keep on doing … For I delight in the law of God, in my inner being, but I see in my members another law waging war against the law of my mind and making me captive to the law of sin that dwells in my members. Wretched man that I am! Who will deliver me from this body of death? (Rom 7:15-24)
When we can’t overcome the evil in us, we feel frustrated.
We let out this frustration at others instead of realizing that we need to deal with the problem inside us.
Why did we feel angry at someone? “He is a hindrance to me because he prevented me from fulfilling my desire to do something.”
Is my desire pleasing to God? If it is, then trust God that He will make a way for you to fulfill your desire.
If it is not, then surrender that desire to God and ask Him to take it away from you.
Two deacons could not see eye to eye. On the surface, they had a clash of personalities. But inside them, they have a desire to prove themselves. They wanted approval from man for their abilities to perform. Each wanted his own way.
Finally, they realized that if what they intend to do is of God, it will come to pass. If what they intend to do is not of God, it will be overthrown. They humbled themselves and agreed to try out one of their plans first before the other.
Let us examine the animosity, friction, or unhappiness we have with others. Can we link it with some sin inside us?  If we can, then put away that sin.  It will manifest itself through our quarrels and fights with others.
(MT)