2 Corinthians 6:11-15

We have spoken freely to you, Corinthians, and opened wide our hearts to you. We are not withholding our affection from you, but you are withholding yours from us. As a fair exchange—I speak as to my children—open wide your hearts also. Do not be yoked together with unbelievers. For what do righteousness and wickedness have in common? Or what fellowship can light have with darkness? What harmony is there between Christ and Belial? Or what does a believer have in common with an unbeliever?