Lamp
Jesus uses this parable (28th in Luke) to illustrate:
Having yourself ready for the master day or night.
Master in this case is Jesus.
The lamp represents the light of God and his son Jesus.
JESUS IS THE LAMP AND GOD IS THE LIGHT.
Background Reading:
Luke 12:35-40 - The Lamp
Watchfulness
35 "Be dressed ready for service and keep your lamps burning, 36like men waiting for their master to return from a wedding banquet, so that when he comes and knocks they can immediately open the door for him. 37 It will be good for those servants whose master finds them watching when he comes. I tell you the truth, he will dress himself to serve, will have them recline at the table and will come and wait on them. 38It will be good for those servants whose master finds them ready, even if he comes in the second or third watch of the night. 39But understand this: If the owner of the house had known at what hour the thief was coming, he would not have let his house be broken into. 40 You also must be ready, because the Son of Man will come at an hour when you do not expect him."
see Candle, Lamp, Light
Some scriptures:
Matthew 5:14-16, 6:22-23, 25:1-13
Mark 4:21
Luke 8:16-18, 11:35-36, 12:35-40, 15:8
John 5:35, 8:12
and there are more.