Holiness means not only to be separated from evil, but primarily to be distinct from the world around us. Because we are separated from the spirit of the world, we can be different and when people look at us, we should be different. Again, this is a command to us to pursue or press forward towards being holy in our life and behavior. In the world, people seek revenge when another has hurt them because of unforgiveness. Or they hold the grudge inside and whenever they can, they attack that person's character.
Bitterness takes control of their spirit and mind and they seek to avenge their hurt.
But as Christians we seek to forgive and release those who have hurt us so that we are both distinct as well as different from the world. Holiness is not difficult because He enables us through His Spirit to forgive, love, understand and accept life without try to cast others down. And third, we are to walk in God's grace . In other words, every believer has an ongoing responsibility to carefully watch over other believers to be sure that they don't lag behind in accepting all of God's blessings, but appropriate God's grace in each circumstance so that bitterness does not rear up its ugly head and take root in their heart. We are to help each other receive, appropriate and walk in God's grace.