Of the six words translated “light” in the New Testament, two, lampas and luchnos, apply almost exclusively to a physical lamp or torch, something portable, and hand-kindled. The only exceptions are Mt.6:22 and its parallel Lk.11:34, where Jesus calls the eye the “light/lamp” of the body, Jn.5:35 where he refers to John the Baptist as a “light”, and Rv.21:23 where “the Lamb is the light” of the holy city. In each of these references, the more common term, phos, is used in the next breath, so it is reasonable to assume that the writers simply felt it necessary to differentiate a source for the “light” they had in mind.
Three of the words are used only twice each: pheggos, (classically, daylight, moonlight, splendor, luster, or delight) as ambient light (Lk.11:33), or moonlight (Mt.24:49 and parallel Mk.13:24); phoster (classically, that which gives light, stars, radiance, or a window) in Phil.2:15 “you shine as lights”, and Rv.21:11 “[light] radiance like a precious stone”; and photismos, (classically, any kind of illumination, frequently metaphorical) in II Cor.4:6 “the light of the knowledge of the glory of God” and 4:4, “the light of the gospel”.
In contrast, the primary word, phos, or in earlier Greek, phaos, used 70 times, could have referred classically to any of these: L/S lists “light of sun or moon, light of a torch, lamp or fire; the light of the eyes; a window; light as a metaphor for deliverance, happiness, or victory; or illumination of the mind.” Bauer adds “the bearers of enlightenment,” whether material, human, or supernatural.
The New Testament appearances of phos can be sorted into several categories – and you may wish to vary these boundaries. (Feel free!) Some clearly refer to ordinary illumination – daylight, firelight, lamplight (Mt.10:27, Mk.14:54, Lk.8:16, 12:3, 22:56; Jn.11:9, Ac.16:29, II Cor.4:6). Others are specifically contrasted with “darkness”, which may be understood simply as a natural state, or in a metaphorical sense of ignorance or evil (Mt.4:16, 6:23; Lk.11:35, Jn.1:5, 3:19-20, 8:12, 11:9; Ac.26:18, Rom.2:19, II Cor.4:6, 6:14,11:14; Eph.5:8, I Jn.1:5).
As was the case in the LXX, visible light occasionally represents the presence of God or one of his messengers (Mt.17:2, Ac.9:3, 12:7, 22:6, 9, 11; Ac.26:13, I Tim.6:16, Rv.21:24, 22:25).
The faithful are termed “children of light” (in contrast to “this generation” or to “darkness”) in Lk.16:8, Jn.12:36, Eph.5:8, I Thes.5:5. They even become a source of light (Mt.5:14,16; Lk.2:32, Ac.13:47, 26:23) to those in ignorance.
Light – or one’s attitude toward illumination – is a clear revealer of people’s allegiance, motives, and activity. John observed that even when light is available, some folks prefer darkness “because their deeds were evil” (Jn.3:19). Quite bluntly, he explains (3:20) “Everyone who practices wickedness hates the light, and does not come to the light, lest his deeds be exposed. (21) But the one who is acting in the truth (see W.S.#26), comes to the light, in order that his deeds may be revealed, that they were performed in [for] God!” Repeatedly, behavior that is hidden or kept secret is assumed to be evil (Eph.5:12-13, I Jn.2:9) – that is the only reason for hiding! Darkness has tried (Jn.1:5) to defeat the light – and failed utterly!
“Children of light” (see above) are to have nothing to do with secrecy and darkness. If only people (especially any designated “leaders” ) in churches would recognize that all secrecy is consistently connected with darkness, not the light of the Lord, how very much pain and damage could be averted!
John reminds his readers (I Jn.2:8) “The darkness is passing away, and the true light is already shining!” Because, as he had written so eloquently in the introduction to his gospel, “Light came into the world”(1:4-9) in the person of the Lord Jesus! Later, (8:12, 9:5, 12:35, 36, 46) he quotes statements of Jesus himself, including two of his early “I AM” statements (W.S.#17), to corroborate that identification. Although James (1:17) speaks of the “Father of Lights”, in the rest of the New Testament, it’s all about Jesus!
Followers of Jesus are urged to “walk in the light” (I Jn. 1:7), “trust in the light” (Jn.12:36) while it is available (also I Jn. 1:7), to “let your light shine” (Mt.5:16) in order that observers may give glory (W.S.#74) to God, to “speak in the light” (Mt.10:27).
“Once you all were darkness, but now (you are) light, in the Lord! Behave as children of light! The harvest of the light (is) in all goodness and justice and truth. Find out what is pleasing to the Lord, and don’t participate with the unfruitful deeds of darkness: rather, rebuke them. The things they do secretly are shameful even to talk about, but everything is being exposed [revealed] by the light. Everything revealed IS light!” (Eph.5:8-14), is probably one of the best descriptions we have of the transformation of life that results from a genuine, wholehearted commitment to the Kingdom of Jesus. There are no exceptions to the complete openness and honesty, and the consequent total avoidance of secrecy or deception, that is expected of Kingdom citizens. “He that loves [keeps loving] his brother, stays in the light” (I Jn.2:10).
For children of light, to put it bluntly, anything that needs to be said or done in darkness / secrecy probably ought never to be said or done at all!
Peter offered an appropriate reminder (I Pet.2:9), “You all are a chosen generation, a royal priesthood, a set-apart [holy] nation, a people especially reserved for [committed to] the purpose of sending out messages about the excellence of the one who called you out of darkness, into his amazing light!”, and Paul (Col.1:12) adds that the Lord not only called us, but “qualified us for a share of the inheritance of his people in the light!” – that glorious “light” of the glory of God in the face of Jesus Christ” (II Cor.4:6), which no darkness can defeat (Jn.1:5)!
May we continually encourage and help one another to “walk as children of light”!