Eph 5:8 for at one time you were darkness, but now you are light in the Lord. Walk as children of light.
The apostle having laid out his first point, that of walking in love, he now transitions to the second point walking in the light. He first calls to attention the former life of darkness (old life). That is to say, being totally blind and ignorant. We were darkness, we gave off no light and darkened others, but now we are light in the Lord and must walk as children of the light (new life).
Mat 5:14 “You are the light of the world. A city set on a hill cannot be hidden.” Note the point of this verse, it does not say you have the light but you are the light. The light reproves and exposes darkness just by its presence. The light from above shines into the hearts of believers, and that light is to be exhibited to men in their characters.
A glorious marriage calls for walking in the light, “the light of the gospel”. Drawing from Christ and walking a walk worthy of our calling in our marriages. We ought to treat our spouses as light and in the light (gospel) both in public and private, it is our call, it is our duty.