There is a biblical anger and then there is sinful anger. The former is anger over things that displease and dishonor God. The latter is often over petty things in our lives that we choose to make a big deal. Paul’s concern here is to make sure that the church addressed sin and interpersonal issues. He didn’t want people to let issues fester; he wanted them to be quick to address problems in the church so that the church could maintain its unity.