Ephesians 5:14 (NIV)
14 This is why it is said: “Wake up, sleeper,
rise from the dead, and Christ will shine on you.”
In order to have a better understanding of what Apostle Paul is saying here, one need to read from verse one of Ephesians chapter 5.
No one has the light of God in him and yet lives in sin. The bible in 1 Timothy 6:16 say that Christ dwells in LIGHT. It could also be said that Christ dwells in the realm of righteousness. (Light)
Darkness is the opposite of light. They that sleep, sleep in the dark.
Take a look from verse one of Ephesians 5, any one who does not follow God's example of living in love (Light) is asleep in darkness and needs to wake up.
Living in Sin is a type of sleeping in darkness. Everyone one in darkness needs light. Therefore Apostle Paul through the holy spirit beckons on us wake up from the darkness of sin unto righteous light of God through Jesus Christ.
It is one who has light that can give light. Jesus Christ is the LIGHT of the World and any one who follows him shall not walk in darkness but shall have the Light of Life.