This is the fourth time Paul uses the idea of living or walking in the ways of God. The practical fruit that he is calling the church of Ephesus to live by is rooted in the spiritual truths found in the first three chapters of Ephesians. In essence Paul is wanting the believers in Ephesus to live out their faith IN CHRIST in a manner worthy of the Gospel (Eph 4:1), not as the Gentiles (Eph 4:17), but to live in love imitating God (Eph 5:1-2).
Children of light
One of the problems believers faced in Ephesus is deception. Even though they were spiritually blessed new creations IN CHRIST and seated in heavenly places, their old nature was still clinging to them. That is why Paul spoke to them about learning to put-off sin and Satan and put-on Jesus Christ. Paul encourages them by saying, “you were once darkness, but now you are light in the Lord. Live as children of light” (Eph 5:8).