But when all things are reproved. As the participle, (phaneroumenon,) which is translated, that which doth make manifest, is in the middle voice, it admits either of a passive or active signification. It may be either rendered, that which is made manifest, or that which doth make manifest. If the passive signification, which is followed by the ancient translator, be preferred, the word light will denote, as formerly, that which gives light, and the meaning will be, that evil works, which had been concealed, will stand out to public view, when they have been made manifest by the word of God: If the participle be taken actively, there will still be two ways of expounding it: 1. Whatever manifests is light; 2. That which manifests anything or all things, is light; taking the singular as put for the plural number. There is no difficulty, as Erasmus dreaded, about the article; for the apostles are not in the habit of adhering very strictly to rule about placing every article, and even among elegant writers this mode of using it would be allowable. The context appears to me to shew clearly that this is Paul's meaning. He had exhorted them to reprove the evil works of unbelievers, and thus to drag them out of darkness; and he now adds, that what he enjoins upon them is the proper business of light -- to make manifest It is Light, he says, which makes all things manifest; and hence it followed that they were unworthy of the name, if they did not bring to light what was involved in darkness.

But all things that are reproved - Margin, discovered. The word used here properly means proved, demonstrated, reproved, or convicted (see the notes on John 16:8); but it seems here to be used in the sense of disclosed, or discovered. The sense is, that "its true nature is demonstrated;" that is, it is made known.
Are made manifest by the light - The sense is, "light is the means of seeing what things are. We discern their form, nature, appearance, by it. So it is with the gospel - the light of the world. It enables us to see the true nature of actions. They are done in darkness, and are like objects in the dark. Their form and nature cannot then be known; but, when the light shines, we see what they are;" compare notes on John 3:20-21.
For whatsoever doth make manifest is light - "Anything which will show the real form and nature of an object, deserves to be called light." Of the truth of this, no one can doubt. The meaning in this connection is, that that system which discloses the true nature of what is done by the pagan, deserves to be considered as "light;" and that the gospel which does this, should be regarded as a system of light and truth. It discloses their odiousness and vileness, and it stands thus in strong contrast with all the false and abominable systems which have upheld or produced those vices.

But all things that are reproved - Dr. Macknight paraphrases this verse as follows: "Now all these reprovable actions, ελεγχομενα, which are practised in celebrating these mysteries, are made manifest as sinful by the Gospel; and, seeing every thing which discovers the true nature of actions is light, the Gospel, which discovers the evil nature of the actions performed in these mysteries, is light."
The apostle speaks against these mysteries as he speaks against fornication, uncleanness, and covetousness; but by no means either borrows expression or similitude from them to illustrate Divine truths; for, as it would be a shame even to speak of those things, surely it would be an abomination to allude to them in the illustration of the doctrines of the Gospel.

But all things that are reproved,.... As all sins should be, by the ministers of the Gospel, and by other saints, and will be by God; either by his Spirit convincing of them, or by his judgments, and the letting out of his wrath and fury, either here or hereafter, for the punishment of them:
are made manifest by the light: either by the saints, who are made light in the Lord, and detect and reprove the sins of others; or by the word of the Lord, which discovers the heinousness of sins; or by Christ the light of the world, who as Judge will bring to light the hidden things of darkness; or by the omniscience of God, to whom darkness and light are both alike
for whatsoever doth make manifest, is light; this is true in things natural and spiritual, whether of the sun in the firmament, or of Christ the sun of righteousness; or of the divine word, or of good men.

that are reproved--rather, "when they are reproved," namely, by you (Ephesians 5:11).
whatsoever doth make manifest--rather, "everything that is (that is, suffers itself to be) made manifest (or 'shone upon,' namely, by your 'reproving,' Ephesians 5:11) is (thenceforth no longer 'darkness,' Ephesians 5:8, but) light." The devil and the wicked will not suffer themselves to be made manifest by the light, but love darkness, though outwardly the light shines round them. Therefore, "light" has no transforming effect on them, so that they do not become light (John 3:19-20). But, says the apostle, you being now light yourselves (Ephesians 5:8), by bringing to light through reproof those who are in darkness, will convert them to light. Your consistent lives and faithful reproofs will be your "armor of light" (Romans 13:12) in making an inroad on the kingdom of darkness.

But all things which are reproved, are thereby dragged out into the light, and made manifest - Shown in their proper colours, by the light. For whatsoever doth make manifest is light - That is, for nothing but light, yea, light from heaven, can make anything manifest.