Few things in the created order have been as instructive for the human race as the concept of light or the contrast between light and darkness. As helpful and healthy as actual light sources are, our dependence on the concept of light as a suitable metaphor for much of the human experience almost rivals our dependence on the real thing. The light/darkness contrast is used with great facility in both verbal and visual communication to convey the importance and benefits of knowledge, ideas, and technology (light), and the disadvantage of being without these things, that is, to be in darkness. The light/darkness contrast has been used effectively in moral terms as well, when virtue is associated with light and immorality is the embodiment of darkness.
It should come as no surprise that the biblical use of this light/darkness motif also incorporates both the intellectual and moral dimensions. The apostle Paul’s description of unbelieving Gentiles in Ephesians 4:17–19 is a good example of this when he writes about their “darkened” understanding. What Paul says here about unregenerate Gentiles is true of all of fallen humanity. Our understanding is indeed darkened, and our walk follows suit. But in this passage the apostle alludes to one of the distinctly Christian nuances of the light/darkness construct — the darkness that is native to fallen humanity alienates us from “the life of God.”
Inherent in this assessment is another Christian nuance of the light/ darkness motif, which is the fact that God is the fullness of what is conveyed in the metaphor of light. This leads us to 1 John 1:5, where we read “that God is light, and in him is no darkness at all.” In describing God as light, John is referring to His absolute moral purity and omniscience. In other words, there is no moral defect, nor is there a lack of knowledge in God. John’s point seems to be that the person and work of Christ, which is what is announced in the gospel message, is the light that brings us into fellowship with God, who is the light. This is consistent with what Paul says in 2 Corinthians 4:3–6: “. . . For God, who said, ‘Let light shine out of darkness,’ has shone in our hearts to give the light of the knowledge of the glory of God in the face of Jesus Christ.” God’s Word in general is described as light (Ps. 119:105), but it is the gospel in particular that is the light that reveals God in fullness and brings us into fellowship with Him. John’s description of God as light in whom there is no darkness at all undergirds the fact of His utter otherness and therefore His inaccessibility to fallen creatures who exist in darkness. The critical link for fellowship between creatures of darkness and a Creator who exists in absolute light is the incarnate Son of God. Without Christ, we remain in a state of darkness and alienation from the life of God.
It is evident from 1 John 1:6–7 that John’s emphasis on the fact that God is light in whom there is no darkness at all is more than a theological abstraction. On the contrary, his concern is practical and pastoral — he admonishes his readers to “walk in the light as he is in the light.” For John, embracing the gospel message brings us into fellowship with God the Father through and with Jesus Christ and with each other (1 John 1:3). The genuine nature of this fellowship is seen in a walk (or manner of living) that reflects and responds to the truth that is revealed in Christ. Once again, we can see a correlation to Paul’s letter to the Ephesians. Having charged them to not walk as the unregenerate Gentiles do (according to their darkened understanding), Paul goes on to remind them of what has been revealed in and by Christ (Eph. 4:17–32). And then in chapter 5, Paul says, “Therefore be imitators of God, as beloved children. And walk in love, as Christ loved us and gave himself up for us, a fragrant offering and sacrifice to God. . . . Therefore do not become partakers with them; for at one time you were darkness, but now you are light in the Lord. Walk as children of light (for the fruit of light is found in all that is good and right and true), and try to discern what is pleasing to the Lord. Take no part in the unfruitful works of darkness, but instead expose them” (vv. 1–2, 7–11). These calls to walk in the light of the knowledge of Christ are not offered as a means of gaining fellowship with God; rather, it is because of the fellowship that we possess by faith in Christ that Paul exhorts his readers — and us — to walk in the light. Psalm 36:9 says, “For with you is the fountain of life; in your light do we see light.” Both John and Paul make the point of full purity and knowledge in God revealed in Christ, received by believers and reflected in their thoughts and walk.
God is indeed light, and in Him there is no darkness at all. By virtue of our fallen condition we are in a state of darkness and are thereby alienated from the life of God. But in Christ we are reconciled to God and are in fellowship with the light. The admonition is that we would reflect that light to the glory of the triune God.