In this next section of Ephesians 4:17-32 Paul tells us that when we practice old ways, ways we walked in when we were unregenerated it is in a sense like we are putting on the old self again. He reminds us that the old self was put off when we came to Christ. Now that we are Christians we have a new self that is being renewed in God's likeness. It's a matter of focus. Our focus is to be on the new self, new behaviors, or as he says in chapter 5:1, "imitators of God."