2 Corinthians 6:14 (NIV)
14Do not be yoked together with unbelievers. For what do righteousness and wickedness have in common? Or what fellowship can light have with darkness?
John 3:19-21 (NIV)
19This is the verdict: Light has come into the world, but men loved darkness instead of light because their deeds were evil.
20Everyone who does evil hates the light, and will not come into the light for fear that his deeds will be exposed.
21But whoever lives by the truth comes into the light, so that it may be seen plainly that what he has done has been done through God.”