That you may show yourselves to be blameless and guiltless, innocent and uncontaminated, children of God without blemish (faultless, unrebukable) in the midst of a crooked and wicked generation [spiritually perverted and perverse], among whom you are seen as bright lights (stars or beacons shining out clearly) in the [dark] world, Philippians 2:15 (AMPC)
Everyone and everything that rejects, opposes, and resists God and His Kingdom is under the control of darkness.
God is Light therefore whatever contradicts Him is darkness. The whole world which is the entire system which people and things without Christ are subjected under is ruled by darkness.
We who have believed in Jesus Christ are in the Kingdom of Light. We are Light. The Life of Christ in us is Light to the world in darkness.
The Love, selflessness, Faith, Peace, forgiveness, rest of God in us is the light we shine out to and in a world full of and ruled by the darkness of selfishness, fear, worry, hatred, despair envy, strife, defeat, failure and death.
We shine out this light holding fast the Word of Life. When we allow the Word of God to dominate our thinking and actions then we dominate the World around us with the Light of this God kind of Life that’s in the Word.