In 1 Corinthians 12:12-27, Paul uses the members of the human body to help us understand how the Church should function. The many members of the human body come in different shapes and sizes. It is quite obvious that a nose is very different from a ear and a toe performs in a manner that is quite different from a tongue.
Even though the two eyes of a person are similar they are still different. That is why many people who wear glasses have different prescriptions for each eye. The mystery is that even though each part is so different from other parts of the body all the parts work in harmony with each other. This is because all the parts of the body are controlled by the brain.
In like manner the Church can work in unity and harmony if all members are controlled by the Head of the body which is Jesus Christ. If each member is in full submission to Jesus then He will bring about a unity among the members that will truly revolutionize the world. Too often we are focused on our differences and either comparing or critiquing other members.
Rather than being concerned about spirituality or the lifestyle of another member we should each be more concerned about our complete surrender to Jesus Christ. When the Head has full control over each member of the Body then the whole body will function effectively (Ephesians 4:13-16) and the world will have no doubt that Jesus Christ is indeed alive.