Every Christian generally understands that the character of God has implications for everyday life. That is to say, whoever God is and however God acts is for us the perfect picture of what we are supposed to be. It is no wonder, then, that a good many believers practice a spineless “tolerance” simply because love, to them, is equivalent to uncritical acceptance. Thus, God is love, or, put differently, God is he who uncritically accepts everyone and everything they believe and practice.
The apostle John (or could it have been Lazarus?), however, had a different understanding of what it means to say, “God is love.” We can get at what he meant by that by looking at what he wrote about God four chapters before the love passage (1 John 4:7ff.).
“This is the message we have heard from [Jesus] and proclaim to you, that God is light, and in him is no darkness at all” (1:5). This one verse sets up the central message of the entire epistle: God’s character demands that we live a certain way. If we want to develop our Christian character, then it would behoove us to look at this “God is light” a little closer.
Even though many ancient religions long before Rome worshiped gods of light, the people of Israel had their own, distinct tradition with respect to the God who is light. At its core, Saint John’s thinking (in 1:5) is latent with Old Testament symbolism. Light was a common symbol for Yahweh, chosen by God himself. On various occasions, God revealed himself in fire and light. His clothes were light and glory (Ps. 104:2; see also Hab. 3:3–4 and 1 Tim. 6:16). Also, God is light in two ways: in revelation (Ps. 27:1; 36:9; Isa. 49:6) and in holiness. The light is transcendent glory; thus its antithesis, darkness, is sin and impurity (see Isa. 5:20). Light symbolizes the absolute perfection of God, as well as the revealed truth of God (Prov. 6:23; Ps. 119:30). Darkness, therefore, is the absence of revelation.
Lightness and darkness were frequently associated with good and evil in ancient times. During the inter-testamental period, a Jewish sect by the Dead Sea exhorted its members to love all the sons of light and hate all the sons of darkness. More importantly for us, however, are the writings of Saint Paul in this regard (Rom. 13:11–13; 1 Cor. 4:5; 2 Cor. 4:6; Eph. 5:8–14; 1 Thess. 5:4–8). One gets the impression that the Apostle to the Gentiles understood this imagery well. Notice, too, that in 1 John 1:5 the writer quickly adds for emphasis after the statement “God is light” that “in him there is no darkness.” In other words, God is revelation, salvation, and holiness, and in him there is no befuddlement, cloudiness, impurity, or abandonment. The point is that living in the darkness is incompatible with claiming to be in fellowship with the God of light (1:6). As was typical, we see that lightness and darkness are given an ethical emphasis, which leads us to see that the apostle is unpacking a moral test that he expects every one of his readers to pass.
This test, this message, is not to be taken as the whole doctrine of salvation (as if he's pushing us on toward moralism). Rather, the apostle John simply argues that if we desire to partake in the blessings of Christ and be in union with God, it is required of us to be conformed to God in a life of holiness. John Calvin quotes from the letter to Titus (2:11–12) at this point in his commentary on 1 John: “Appeared has the saving grace of God to all, that denying ungodliness and worldly lusts, we may live soberly and righteously and holy in this world.” We need to understand that Saint John is saying the same thing as Saint Paul, just in metaphor: walk in the light, because God is light.
Learning about God, then, is to learn how to live. So if we are to love, because God is love, then we must first understand that he is a blazing glory. Far from being a huggable old fellow, our Lord is a glaring light, devouring flame, burning bush, pillar of fire.