Matthew 6:23

but if your eye is unsound, your whole body will be dark. If, therefore, your very light is darkness, how deep the darkness will be!

Luke 11:34-35

Your eye is the lamp of your body. When your eye is sound, your whole body is light, but when it is unsound, your body is dark.

Ephesians 5:8

For once you were sheer darkness, but now, as Christians, you are light itself. You must live like children of light,

Treasury of Scripture Knowledge

Summary

Then I saw that wisdom excelleth folly, as far as light excelleth darkness.

Bible References

Light

Matthew 6:23
but if your eye is unsound, your whole body will be dark. If, therefore, your very light is darkness, how deep the darkness will be!
Luke 11:34
Your eye is the lamp of your body. When your eye is sound, your whole body is light, but when it is unsound, your body is dark.
Ephesians 5:8
For once you were sheer darkness, but now, as Christians, you are light itself. You must live like children of light,