Anger is not necessarily sin.
The problem is what we do with the anger we feel. Jonah had the other kind of anger - the kind that was going to irritate no matter what happened.
Jesus expressed anger time and again. Jesus knew what to do with his anger and tells us what to do with ours.
Jesus had no problem whatsoever in saying how angry he was with the scribes, Pharisees, religious leaders and those who made the temple into a trading post. He was really angry, and he did something constructive with his anger. He gave it voice and direction. He told the religious movers and shakers what a bunch a hypocrites they were and he fired off the seven deadly woes at them, expressing in minute detail what was going to happen to them for their callous approach to their religious duties.
Do not let your anger worsen. Go and get right with the cause of your anger and put that anger to rest.
Get angry for the right reason. There is good reason to get angry. In scripture, especially in the Old Testament, God is depicted time and again as an angry God. But God is always angry for good reason -
Jonah 4:1,4,9b
But this was very displeasing to Jonah, and he became angry. And the Lord said, "Is it right for you to be angry?" And he said, "Yes, angry enough to die."
John 2:14-15
In the temple Jesus found people selling cattle, sheep and doves, and money changers seated at their tables. Making a whip of cords, he drove all of them out of the temple.
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