The Hebrew term ʼohr and the Greek term phos refer to that which emanates from a light-giving body such as a lamp (Jer 25:10) or the sun, as well as to the opposite of darkness, literally and figuratively. (Isa 5:20; Joh 11:10, 11) It is generally believed that light consists of energy particles that have wave properties. To this day, however, man still cannot give a complete answer to the question propounded over three millenniums ago by the Creator of light: “Where, now, is the way by which the light distributes itself?”​—Job 38:24.

Light from the sun is a combination of colors, with each color having a different wavelength. The color of an object is determined by the particular portion of the light reflected by its surface. Thus light furnishes the many hues that delight the eye of man. It is also essential for earthly life​—plant, animal, and human—​to continue.

The Source of Light. Jehovah God is the Former of light and the Creator of darkness. (Isa 45:7) It was on the first creative day that he said: “Let light come to be.” (Ge 1:3) Earlier he had created the heavens (including “the great lights”​—the sun, moon, and stars; compare Ps 136:7-9) and the earth. (Ge 1:1) So the bringing of light into existence with reference to the earth apparently involved gradually removing whatever had formerly obstructed the sun’s rays from reaching this planet. And the “division” between light and darkness must have come about through the rotation of the earth as it moved around the sun. (Ge 1:4, 5) Much later Jehovah plagued the sun-worshiping Egyptians with darkness, a darkness that did not affect the Israelites. (Ex 10:21-23) In leading his people out of Egypt, he provided light by means of a pillar of fire.​—Ex 13:21; 14:19, 20; Ps 78:14.

The Scriptures repeatedly associate light with its Creator. Stated the psalmist: “O Jehovah my God, you have proved very great. With dignity and splendor you have clothed yourself, enwrapping yourself with light as with a garment.” (Ps 104:1, 2) This declaration harmonizes well with Ezekiel’s description of what he saw in vision: “I got to see something like the glow of electrum, like the appearance of fire all around inside thereof, from the appearance of his hips and upward; and from the appearance of his hips and downward I saw something like the appearance of fire, and he had a brightness all around. There was something like the appearance of the bow that occurs in a cloud mass on the day of a pouring rain. That is how the appearance was of the brightness round about. It was the appearance of the likeness of the glory of Jehovah.” (Eze 1:27, 28) Centuries earlier, just a partial manifestation of that glory caused Moses’ face to emit rays.​—Ex 33:22, 23; 34:29, 30.

“God is light and there is no darkness at all in union with him.” (1Jo 1:5) He is righteous, upright, and holy (De 32:4; Re 4:8), having nothing in common with the degrading and unclean practices commonly linked with darkness. (Compare Job 24:14-16; 2Co 6:14; 1Th 5:7, 8.) Therefore persons who are walking in the darkness by manifesting hatred for their brother and who are not practicing the truth could never be in union with him.​—1Jo 1:6; 2:9-11.

Jehovah is “the Father of the celestial lights.” (Jas 1:17) Not only is he the “Giver of the sun for  light by day, the statutes of the moon and the stars for light by night” (Jer 31:35) but he is also the Source of all spiritual enlightenment. (2Co 4:6) His law, judicial decisions, and word are a light to those allowing themselves to be guided by them. (Ps 43:3; 119:105; Pr 6:23; Isa 51:4) The psalmist declared: “By light from you we can see light.” (Ps 36:9; compare Ps 27:1; 43:3.) Just as the light of the sun continues to get brighter from dawn until “the day is firmly established,” so the path of the righteous ones, illuminated by godly wisdom, gets lighter and lighter. (Pr 4:18) To follow the course that Jehovah outlines is to walk in his light. (Isa 2:3-5) On the other hand, when a person looks at things in an impure way or with evil design, he is in great spiritual darkness. As Jesus put it: “If your eye is wicked, your whole body will be dark. If in reality the light that is in you is darkness, how great that darkness is!”​—Mt 6:23; compare De 15:9; 28:54-57; Pr 28:22; 2Pe 2:14.

Light and the Son of God. Since his resurrection and ascension to heaven, Christ Jesus, “the King of those who rule as kings and Lord of those who rule as lords,” “dwells in unapproachable light.” That light is so glorious that it makes it impossible for weak human eyes to behold him. (1Ti 6:15, 16) In fact, one man, Saul (Paul) of Tarsus was blinded by the light from heaven seen by him at the time the glorified Son of God revealed himself to this persecutor of Jesus’ followers.​—Ac 9:3-8; 22:6-11.

During his earthly ministry Jesus Christ was a light, furnishing spiritual enlightenment concerning God’s purposes and will for those who would gain divine favor. (Joh 9:5; compare Isa 42:6, 7; 61:1, 2; Lu 4:18-21.) Initially, only “the lost sheep of the house of Israel” received benefit from that “great light.” (Isa 9:1, 2; Mt 4:13-16; 15:24) But spiritual enlightenment was not to be limited just to the natural Jews and proselytes. (Joh 1:4-9; compare Ac 13:46, 47.) When the infant Jesus was presented at the temple, aged Simeon referred to him as “a light for removing the veil from the nations.” (Lu 2:32) As Paul explained to the Ephesians, uncircumcised non-Jews had been in the dark respecting God and his purposes: “Formerly you were people of the nations as to flesh; ‘uncircumcision’ you were called by that which is called ‘circumcision’ made in the flesh with hands​—that you were at that particular time without Christ, alienated from the state of Israel and strangers to the covenants of the promise, and you had no hope and were without God in the world.” (Eph 2:11, 12) However, when the good news about the Christ was brought to the non-Jews, those who responded favorably were ‘called out of darkness into God’s wonderful light.’ (1Pe 2:9) But others continued to allow the one who transforms himself into “an angel of light” or enlightenment (2Co 11:14), “the god of this system of things,” to blind them so ‘that the illumination of the good news about the Christ might not shine through.’ (2Co 4:4) They preferred darkness, for they wanted to continue in their selfish course.​—Compare Joh 3:19, 20.

Followers of Christ Become Lights. Those who exercised faith in Christ Jesus as “the light of the world” and became his followers themselves came to be “sons of light.” (Joh 3:21; 8:12; 12:35, 36, 46) They made known to others the requirements for gaining God’s favor and life, doing so “in the light,” that is, openly. (Mt 10:27) Similarly, John the Baptizer had served as a light when “preaching baptism in symbol of repentance” and pointing forward to Messiah’s coming. (Lu 3:3, 15-17; Joh 5:35) Also, by their fine works, by word and example, followers of Christ let their light shine. (Mt 5:14, 16; compare Ro 2:17-24.) “The fruitage of the light consists of every sort of goodness and righteousness and truth.” It therefore exposes the baseness of the shameful works belonging to darkness (fornication, uncleanness of every kind, greediness, and the like) practiced by “the sons of disobedience.” As a result these shameful works are seen in their true light and, in the sense of being manifested as things condemned by God, become light themselves. (Eph 5:3-18; compare 1Th 5:4-9.) Equipped with “weapons of the light,” the spiritual armor from God, Christians wage warfare “against the governments, against the authorities, against the world rulers of this darkness, against the wicked spirit forces in the heavenly places” and are enabled thereby to stand firm as approved servants of God.​—Ro 13:12-14; Eph 6:11-18.

Other Figurative Uses. The Scriptures contain many figurative references to light. Ability to see is meant by the words “the light of my own eyes.” (Ps 38:10) For God to “give light” to someone means that he gives them life or allows them to continue living. (Job 3:20, 23; compare Ps 56:13.) “Children that have seen no light” are those who are born dead. (Job 3:16; compare Ps 49:19.) “It is good for the eyes to see the sun” may be understood to mean ‘it is good to be alive.’​—Ec 11:7.

Morning light is picturesquely described as ‘taking hold of the ends of the earth and shaking the wicked out of it,’ because dawn disperses evildoers. Darkness is their “light,” for they are accustomed to carrying out their evil deeds under its cover, and this figurative “light” is taken from  them by the literal light of dawn.​—Job 38:12-15; compare Job 24:15-17.

As the light of the sun is clearly observable, thus Jehovah’s adverse judgments are obvious. This is alluded to at Hosea 6:5: “The judgments upon you will be as the light that goes forth.”

The ‘light of God’s face’ means divine favor. (Ps 44:3; 89:15) “Lift up the light of your face upon us” is an expression meaning ‘show us favor.’ (Ps 4:6) Similarly, the favor of a ruler is referred to as “the light of the king’s face.”​—Pr 16:15.

Light may denote brightness or cheerfulness, the opposite of gloom. (Job 30:26) This may explain the words of Job (29:24): “The light of my face they would not cast down.” Although others were gloomy and dejected, this did not cause Job to become of like disposition.

A bright prospect, such as salvation or deliverance, is at times referred to under the figure of light. (Es 8:16; Ps 97:11; Isa 30:26; Mic 7:8, 9) Jehovah’s causing his glory to shine forth upon Zion pointed forward to her deliverance from a captive state. As a result Zion was to become a source of enlightenment to the nations. (Isa 60:1-3, 19, 20; compare Re 21:24; 22:5.) On the other hand, for the sun, moon, and stars not to give their light would signify calamity.​—Isa 13:10, 11; Jer 4:23; Eze 32:7, 8; Mt 24:29.