“For at one time you were darkness, but now you are light in the Lord. Walk as children of light” – Ephesians 5:8
Surprisingly, the readers are not presented simply as having been in the realm of darkness and being now in the sphere of light, although this would have been true enough (cf. John 8:12 ; 1 Pet. 2:9 ; 1 John 1:5-7 ; 2:9 ). It is not their environment or the surroundings in which they and the rest of humanity live that is in view. Rather, they themselves were once darkness, but now they are light in the Lord. Those ruled by the dominion of darkness or of light represent that dominion in their own persons. So when they were converted, it was their lives, not their surroundings, that were changed from darkness to light. This radical transformation had taken place in the Lord. He is the one who has made the decisive difference, and it is through their union with him that they have entered a new dominion and become light.
The Letter to the Ephesians (Grand Rapids, MI; Eerdmans Publishing Company; 1999) Commentary on Ephesians 5:8.