A Christian is “at the same time justified and a sinner” (simul iustus et peccator). It is one of the more well-known phrases of the Reformation. God in his grace and mercy has declared the Christian to be righteous due to the atoning work of Jesus Christ. And what God declares something to be, truly is. And yet at the same time, sin is still at work in our flesh.
"Do we have to forgive people who aren't sorry?" How would you respond? Our instinct can be to rush in with some kind of ‘yes/no’ answer. What we may fail to do is consider whether or not answering the question as asked is the most helpful response.