Do not take revenge, my dear friends, but leave room for God’s wrath, for it is written: “It is mine to avenge; I will repay,” says the Lord.

In this day of constant lawsuits and incessant demands for legal rights, Paul’s command sounds almost impossible. When someone hurts you deeply, instead of giving him what he deserves, Paul says to befriend him. Why does Paul tell us to forgive our enemies? (1) Forgiveness may break a cycle of retaliation and lead to mutual reconciliation. (2) It may make the enemy feel ashamed and change his or her ways. (3) By contrast, repaying evil for evil hurts you just as much as it hurts your enemy. Even if your enemy never repents, forgiving him or her will free you of a heavy load of bitterness. 12:19–21 Forgiveness involves both attitudes and actions. If you find it difficult to feel forgiving toward someone who has hurt you, try responding with kind actions. If appropriate, tell this person that you would like to heal your relationship. Lend a helping hand. Send him or her a gift. Smile at him or her. Many times you will discover that right actions lead to right feelings.

Tyndale House Publishers. Life Application Study Bible, NIV 

My dear brothers and sisters, take note of this: Everyone should be quick to listen, slow to speak and slow to become angry, because human anger does not produce the righteousness that God desires.

When we talk too much and listen too little, we communicate to others that we think our ideas are much more important than theirs. James wisely advises us to reverse this process. Put a mental stopwatch on your conversations and keep track of how much you talk and how much you listen. When people talk with you, do they feel that their viewpoints and ideas have value?

These verses speak of anger that erupts when our egos are bruised—“I am hurt”; “My opinions are not being heard.” When injustice and sin occur, we should become angry because others are being hurt. But we should not become angry when we fail to win an argument or when we feel offended or neglected. Selfish anger never helps anybody.

Tyndale House Publishers. Life Application Study Bible, NIV

What causes fights and quarrels among you? Don’t they come from your desires that battle within you? You desire but do not have, so you kill. You covet but you cannot get what you want, so you quarrel and fight. You do not have because you do not ask God. When you ask, you do not receive, because you ask with wrong motives, that you may spend what you get on your pleasures.

Conflicts and disputes among believers are always harmful. James explains that these quarrels result from evil desires battling within us—we want more possessions, more money, higher status, more recognition. When we want badly enough to fulfill these desires, we fight in order to do so. Instead of aggressively grabbing what we want, we should submit ourselves to God, ask God to help us get rid of our selfish desires, and trust him to give us what we really need.

James mentions the most common problems in prayer: not asking, asking for the wrong things, asking for the wrong reasons. Do you talk to God at all? When you do, what do you talk about? Do you ask only to satisfy your desires? Do you seek God’s approval for what you already plan to do? Your prayers will become powerful when you allow God to change your desires so that they perfectly correspond to his will for you (1 John 3:21, 22).

Tyndale House Publishers. Life Application Study Bible, NIV

“In your anger do not sin”. Do not let the sun go down while you are still angry, and do not give the devil a foothold.

The Bible doesn’t tell us that we shouldn’t feel angry, but it points out that it is important to handle our anger properly. If vented thoughtlessly, anger can hurt others and destroy relationships. If bottled up inside, it can cause us to become bitter and destroy us from within. Paul tells us to deal with our anger immediately in a way that builds relationships rather than destroys them. If we nurse our anger, we will give Satan an opportunity to divide us. Are you angry with someone right now? What can you do to resolve your differences? Don’t let the day end before you begin to work on mending your relationship.

Tyndale House Publishers. Life Application Study Bible, NIV 

Refrain from anger and turn from wrath; do not fret—it leads only to evil. For those who are evil will be destroyed, but those who hope in the LORD will inherit the land.

Anger and worry (fretting) are two very destructive emotions. They reveal a lack of faith that God loves us and is in control. We should not worry; instead, we should trust in God, giving ourselves to him for his use and safekeeping. When you dwell on your problems, you will become anxious and angry. But if you concentrate on God and his goodness, you will find peace. Where do you focus your attention?

Tyndale House Publishers. Life Application Study Bible, NIV