Well a non believer of Christ is someone who does not adhere, advocate and uphold the Christian values. Sometimes it is a way of denying what people tends to perceive as real but "very not so human". Too much acts of kindness, humility and forgiveness are works of foolish people but are actually the lessons portrayed in most of Jesus' teachings. So i believe that in the eyes of God both believers and non believers of Christianity are responsible to follow or conform with the values that they adhere regardless of whatever religion it is. What is important is that each and everyone has faith and believes that there is one supreme being who maybe known in different names. We all have the right to choose the religion where we want to belong. it may not be called Christianity, He may not be call Christ but still it is believing in a Supreme Being.