Light represents truths from God's word!
Psalm 43:3 O send out thy light and thy truth: let them lead me; let them bring me unto thy holy hill, and to thy tabernacles.
Psalm 119:105 Thy word is a lamp unto my feet, and a light unto my path.
John 17:17 Sanctify them through thy truth: thy word is truth. (This is Jesus speaking here. His word is what)?
Luke 11:33 No man, when he hath lighted a candle, putteth it in a secret place, neither under a bushel, but on a candlestick, that they which come in may see the light. (The light is truth from the Word. When God gives you a truth, let it shine and share it with others so they can see it and understand it also. See Matthew 5:15-16; Mark 4:21-22).
Luke 11:34 The light of the body is the eye: therefore when thine eye is single, thy whole body also is full of light; but when thine eye is evil, thy body also is full of darkness. (The eye is the mirror to the soul. When your eye is good, your whole body is filled with light [truth, peace, righteousness, fruits of the spirit]. But when it is bad, your body is filled with darkness [deceit, evil, unrighteousness, fruits of the flesh]).
Luke 11:35 Take heed therefore that the light which is in thee be not darkness. (Make sure that the light you have is the truth from God's word, not deceit from commandments and doctrines of men).
Luke 11:36 If thy whole body therefore be full of light, having no part dark, the whole shall be full of light, as when the bright shining of a candle doth give thee light. (Others can see and sense this, the shining of the Holy Spirit; being a good example to others by displaying good fruits of the spirit; see Galatians 5:22-23).
We know billions live in daily rebellion against their Creator and may be doomed for eternity unless they learn the truth and accept Jesus Christ (see the light). Thus, by sharing His truths, and not being selfish with those truths, millions perhaps billions can hear those truths of God's word in this spiritually-dark world and see the light. This doesn't mean we have to get out on a street corner and preach loudly, ramming it down peoples throats. A lot of times we can drive people away from God by being too forceful, preaching hellfire and damnation (false doctrines), etc. We can accomplish truth sharing, in most cases, just by being a good example to others. They may see what we have (good fruits of the spirit, Galatians 5:22-23) and become interested in acquiring some for themselves (help bring them closer to God, not drive them away).
John 3:20 For every one that doeth evil hateth the light, neither cometh to the light, lest his deeds should be reproved.
[Light symbolizes God and His truth; darkness equals the opposite, everything that is anti-God: the wicked, evil, liars and lying, deceit, etc. All who do evil hate the truth, they fear their sins will be exposed; they fear accountability, they are ashamed. See Ephesians 5:12-13. Hopefully, some can even be brought to repentance when their sin is exposed].
Some of the many pertinent verses: Psalm 96:3, 119:142 & 160; Matthew 24:14, 28:19-20; Mark 16:15; John 1:1-9, 8:31-32, 14:6; Acts 26:18; Ephesians 4:25 (share the truth with others); 1 Thessalonians 5:5.
Keep studying and study the Bible completely, cover to cover. Connect the dots and gain a more complete picture of what God wants each of us to know.