I was taught that anger is sin, so every time I feel it I feel guilty on top of it. Is being angry actually wrong?

“And I was very angry when I heard their cry and these words. Then I consulted with myself, and I rebuked the nobles, and the rulers, and said unto them, Ye exact usury, every one of his brother. And I set a great assembly against them.”

Nehemiah was governor in Jerusalem, rebuilding the wall, when he learned that wealthy Jews were charging their own starving countrymen interest and taking their children as collateral. His reaction was fury, and the text records it without apology. What he did next is the point: he thought it through first, then confronted the people responsible in public. The anger got him moving, and deliberation decided what it was allowed to do.

“And when he had looked round about on them with anger, being grieved for the hardness of their hearts, he saith unto the man, Stretch forth thine hand. And he stretched it out: and his hand was restored whole as the other.”

Mark describes a man with a withered hand in a synagogue on the Sabbath, and religious leaders watching to see whether Jesus would heal and hand them an accusation. Mark records that Jesus looked round at them with anger and with grief together. If anger were sin in itself, that sentence could not stand in the gospel. Anger here is what love does when it runs into something that harms people.