In Chapters 1-3 Paul sets out the teaching of the decrees and purposes of God for his people the Church universal. In chapters 4-6 God demands that they live as befits their new relationship. What is claimed with the lips must be backed up by daily living.
Sanctification is not a patching up of the old life. It is a new principle of life to be nurtured, a life-long deepening experience. That is why when we reached heaven we shall feel completely at home! Let the old sinner in you be starved and put to death (mortification), and instead vigorously feed the new life. I ask myself the question, “How am I doing?” Ask yourself the same question.