Anger is an emotion that all of us experience at times. It arises in us for many reasons, some of which are okay, and some of which are not. There is anger that is acceptable in the eyes of God, and there is anger that He finds unacceptable. We may become angry because of jealousy, just as Cain became angry when God accepted Abel's offering, but rejected Cain's (Genesis 4:4-5). Our anger may stem from pride, just as Jonah's pride caused him to be angry when God spared the people of Nineveh, people who were Gentiles (Jonah 4:1). Anger that stems from jealousy and pride is unacceptable anger. But, sometimes anger is justified, such as the anger that Moses felt when he came down from Mount Sinai to find the Israelites worshipping a golden calf (Exodus 32:19).
The problem with unacceptable anger is not so much the anger itself, but the results of the anger. Proverbs 30:33 tells us that anger can cause strife. When Cain became angry out of jealousy, what was the result of his anger? He killed his own brother (Genesis 4:8). Unacceptable anger can bring God's judgment on us. Jesus talked about this in the Sermon on the Mount, saying that anyone who is angry with a brother or sister is liable to judgment (Matthew 5:22). Anger that is allowed to fester can lead us into sin. In his letter to the Ephesians, Paul warned against letting the sun go down on anger (Ephesians 4:26).
God's Word is clear on the subject of anger and how we should deal with it. God knows that we will feel anger, but His Word tells us that, in our anger, we must not sin (Psalm 4:4; Ephesians 4:26). We must be slow to anger. Ecclesiastes 7:9 says that we should not be quick to become angry because anger lives in the hearts of fools. And James 1:19 tells us that we should be quick to listen, slow to speak, and slow to get angry. We should make it our goal to put away anger, to steer clear of it (Ephesians 4:31; Colossians 3:8). God desires that His people should be united, praying as one without any anger or quarreling (1 Timothy 2:8).