Matthew 21:12-13

"Then Jesus went into the temple of God and drove out all those who bought and sold in the temple, and overturned the tables of the money changers and the seats of those who sold doves."

"And he said to them, 'It is written, 'My house shall be called a house of prayer, ' but you have made it a 'den of thieves'.'"

(These verses and others prove that there is a such thing as righteous anger. However, it is far wiser for us to never be anger, even if it were to start out righteous. In our sinful state, our righteous anger would quickly deteriorate into something sinful, and so it is wiser to avoid all anger.)