Be angry but do not sin; do not let the sun set on your anger, and do not leave room for the devil. 

Ephesians 4:25-26

Paul writes to the Ephesians to teach them about how to live in community with one another. He tells them that it is okay to be angry, but not okay to sin. They can get angry and still choose to avoid sin. He then says they should get rid of their anger quickly because anger gives the devil room to work in their lives. 

When we get offended, it often turns to anger. If we do not deal with the anger of being offended, we give the devil and evil spirits room in our hearts to make us bitter and entitled and self-centered. It is how marriages are destroyed and relationships are ended.

Have you let the sun set on a past offense? Has it brought about bitterness? If so, repent of it. Ask God for his mercy and grace to bring healing to your heart.