What did Paul mean when he says it? How must be our relationship with unbelievers?
Well, according to some interpretations of Mark 9:49-50, it means that we should say things that will ‘preserve’ them forever in unbelief. 
What did Paul mean when he says it? How must be our relationship with unbelievers?
Well, according to some interpretations of Mark 9:49-50, it means that we should say things that will ‘preserve’ them forever in unbelief.