Matthew 6:23

But if thine eye be vitiated, thy whole body will be darkened. If therefore the light which is in thee be darkness, how great is that darkness!

Luke 11:34-35

The lamp of the body is the eye: when therefore thine eye is clear, thy whole body will be luminous, but if it be vitiated, thy whole body will be darkened.

Ephesians 5:8

For ye were formerly darkness, but now are ye light in the Lord: walk as 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 thine eye be vitiated, thy whole body will be darkened. If therefore the light which is in thee be darkness, how great is that darkness!
Luke 11:34
The lamp of the body is the eye: when therefore thine eye is clear, thy whole body will be luminous, but if it be vitiated, thy whole body will be darkened.
Ephesians 5:8
For ye were formerly darkness, but now are ye light in the Lord: walk as children of light;