“Circumstance does not make the man; it reveals him to himself,” wrote the British philosopher James Allen. That’s why when we become impatient, we cannot blame other people or our circumstances. According to Jerry Bridges,
They merely provide an opportunity for the flesh to assert itself. The actual cause of our impatience lies within our own hearts, in our own attitude of insisting that others around us conform to our expectations. 
When we become impatient, we have no one to blame but ourselves. According to James 4:1, the wars outside are caused by the wars inside. There is a raging war within!
What causes quarrels and what causes fights among you? Is it not this, that your passions are at war within you? (ESV. Emphasis added)
That means we have conflicts within which leads to conflicts outside. The Contemporary English Version translated the second half of the verse this way: “Isn’t it because you are full of selfish desires that fight to control your body?” We are at war with ourselves.
People who are at war with themselves because of selfish desires are always unhappy people. They never enjoy life. Instead of being thankful for the blessings they do have, they complain about the blessings they do not have. They cannot get along with other people because they are always envying others for what they have and do. They are always looking for that “magic something” that will change their lives, when the real problem is within their own hearts. 
So how do we deal with this war within? First, we need to have peace WITH God. According to Romans 5:1, “Therefore, since we have been justified by faith, we have peace with God through our Lord Jesus Christ.” Let us make sure we have already put our faith in our Lord Jesus Christ as our Savior. These conflicts within us are a result of our spiritual conflict with God. (Read James 4:8-10.)
When we have peace with God, then we will have “the peace OF God, which surpasses all understanding, will guard [our] hearts and [our] minds in Christ Jesus.” (Philippians 4:7) Once we have settled the conflict inside of us, we can now deal with the conflicts outside of us.
Now that doesn’t mean that once we are Christians, all our conflicts are automatically resolved. That’s far from the truth. But once we settle our differences with God, we are in the best position to settle our differences with others.
“Slow to Anger” Step
When we become angry, we usually blame those who “made” us angry. But James 4:1 says otherwise.
What causes quarrels and what causes fights among you? Is it not this, that your passions are at war within you?
Reflect on the last time you were angry. What were the passions within you that drove you to be angry?
 Jerry Bridges, Respectable Sins: Confronting the Sins We Tolerate (Colorado Springs, CO: NavPress, 2007), 117.
 Warren Wiersbe, “James” in The Bible Exposition Commentary (Wheaton, IL: Victor Books, 1989) 365.