8 for at one time you were darkness, but now you are light in the Lord. Walk as children of light
9 (for the fruit of light is found in all that is good and right and true),
10 and try to discern what is pleasing to the Lord.
11 Take no part in the unfruitful works of darkness, but instead expose them.
12 For it is shameful even to speak of the things that they do in secret.
13 But when anything is exposed by the light, it becomes visible,
14 for anything that becomes visible is light. Therefore it says, "Awake, O sleeper, and arise from the dead, and Christ will shine on you."
Those of the light are more than capable of walking in darkness,else Paul would not have written this admonition.
Part of the "unfruitful works of darkness" is our speaking of the sinful actions which those who walk in darkness do. Paul says it is shameful to speak f these things, yet the visible professing church, voyeuristic to the extreme, can't shut up about anyone's wrongdoings as long as theirs' are not part of the discussion.
The saints are told to expose the deeds of darkness, but not by gossiping about these deeds and their perpetrators.
The question before the children of light is; how is this done?
Verses 8; 13 and 14 explain it all. As with all things pertaining to salvation and the kingdom of God, it does not originate with us.
Therefore we are light because we are declared by the Lord to be light.
14 "You are the light of the world. A city set on a hill cannot be hidden.
15 Nor do people light a lamp and put it under a basket, but on a stand, and it gives light to all in the house.
16 In the same way, let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven.
The light in its essence naturally overcomes darkness and exposes all that is hidden in the dark. (This is not "sin-sniffing")
4 In him was life, and the life was the light of men.
5 The light shines in the darkness, and the darkness has not overcome it.
The light reveals both the regenerate, and the unregenerate to the glory of God. (Romans 9:22-24)
19 And this is the judgment: the light has come into the world, and people loved the darkness rather than the light because their works were evil.
20 For everyone who does wicked things hates the light and does not come to the light, lest his works should be exposed.
21 But whoever does what is true comes to the light, so that it may be clearly seen that his works have been carried out in God."
The church is not here to rub the sinner's nose in his "mess". The church is here to proclaim the one who is light to His own who are yet still in the dark.
John 8:12 Again Jesus spoke to them, saying, "I am the light of the world. Whoever follows me will not walk in darkness, but will have the light of life."
Soli Deo Gloria