“This is the message which we have heard from Him and declare to you,
that God is light and in Him is no darkness at all.” (1 John 1:5, NKJV) 

If you were to send a message of truth to an atheist that would rock their world, what would it be? Likely, it would be “God exists.” Adoption of that single truth would require deconstruction of everything they have believed and require reconstruction of a radically different worldview. 

John’s opening salvo of truth does the same for us. “This is the message which we have heard from Him and declare to you, that God is light and in Him is no darkness at all” (1 John 1:5). With that cornerstone in place, our building takes shape. If John’s reason for writing his epistle has to with how we can know we have eternal life (1 John 5:13), then front and center must be the person of God. 

What does it mean for God to be light? Sometimes we understand something by looking at its contrast, what it is not. John takes that approach by going on to say that “in Him is no darkness at all.” It’s clear that John is speaking in absolute terms. God is exclusively and continually light. James describes Him as “the Father of lights, with whom there is no variation or shadow of turning” (Jas. 1:17). 

For John light and darkness reflect spiritual dimensions, moral realms, much as Paul does in describing the kingdom of light and kingdom of darkness (Col. 1:12-14). Light reflects that which is good and true; it holds life rather than death. Paul highlights the character of light and the moral imperative associated with it: “For you were once darkness, but now you are light in the Lord. Walk as children of light (for the fruit of the Spirit is in all goodness, righteousness, and truth), finding out what is acceptable to the Lord” (Eph. 5:8–10; see also 1 Thess. 5:4-5). 

We are called to goodness, righteousness, and truth but that call begins with our relationship with God who is light. We are light in the Lord and therefore we are to be light. John anchors his moral imperative in our fellowship with God. “If we say that we have fellowship with Him, and walk in darkness, we lie and do not practice the truth” (1 John 1:6). 

What John is telling us is that our union with Christ and communion with the Father will show up in the life and light of new relationship with the God who is light. Only then can we have confidence that “the blood of Jesus Christ His Son cleanses us from all sin” (1 John 1:7). The sampled fruit of God’s handiwork of grace enables us to know that we have true life in Christ. 

John bids us to take a look at ourselves. Does our heart incline to God? Are we experiencing a greater dis-ease with sin and greater desire for righteousness and truth? 

What bearing does that fact that God is light have on our assurance of salvation?