1 Corinthians 15:33
Don’t let anyone deceive you. Associating with bad people will ruin decent people.

2 Corinthians 6:14-15
Stop forming inappropriate relationships with unbelievers. Can right and wrong be partners? Can light have anything in common with darkness? Can Christ agree with the devil? Can a believer share life with an unbeliever?

Matthew 18:6
These little ones believe in me. It would be best for the person who causes one of them to lose faith to be drowned in the sea with a large stone hung around his neck.