For you are the light that shines in the darkness, for the Spirit of God lives within you. Preach the gospel to others, and tell them about the light [Jesus] who lives in your heart for their salvation.
4 Life was in Him, and that life was the light of men. 5 That light shines in the darkness, yet the darkness did not overcome it.
Whenever Light is present, darkness cannot remain; Light can never be put out because it extinguishes darkness. If you want the dark to go away, turn on the light. Darkness cannot exist while the Light is present but once it is gone, darkness returns. If a person is devoid of God in their heart, the only thing present in his/her heart is pure darkness regardless of how they appear to be outwardly. Those who reject Christ [the Light] darkness will prevail in their life. Darkness cannot overcome the Light but Light overcomes the darkness. If your life is full of darkness [living a life in complete sin, no regard for God or people] and you want a change in the right direction, the only way to take out the darkness in your life is by turning on the Light, inviting Jesus Christ into your heart.
9 If you confess with your mouth, “Jesus is Lord,” and believe in your heart that God raised Him from the dead, you will be saved. 10 One believes with the heart, resulting in righteousness, and one confesses with the mouth, resulting in salvation. 11 Now the Scripture says, Everyone who believes on Him will not be put to shame, 12 for there is no distinction between Jew and Greek, since the same Lord of all is rich to all who call on Him. 13 For everyone who calls on the name of the Lord will be saved.
1 John 1:5
Now this is the message we have heard from Him and declare to you: God is light, and there is absolutely no darkness in Him.
Light is the source of life, plants need it to grow. Light reveals things hidden in the dark and makes the path clear (Psalms 119:105 Your word is a lamp for my feet and a light on my path). Light gives warmth and brings a dying body back to life. What does it mean that God is Light? By God being Light, darkness has no place in Him. No wickedness, bad intentions, malice, corruption, going back on His Word and any other form of evil can be found in God, period. God’s goodness, power, wisdom, beauty, love, and splendor reflects His Light (Habakkuk 3:4 His brilliance is like light; rays are flashing from His hand. This is where His power is hidden). As Christians, we must reflect the light of Christ in our lives. You might be the only light that your friends and family have, so make sure you are living a life according to the Scripture. How else can you get their attention but by flashing a light so to speak in their face, the light which is the message of Christ.