Not only do we have an intelligent relationship with the other members of the body of Christ, we have an intimate relationship.
For just as you have many members in one physical body and those members differ in their functions, so we, though many in number, compose one body in Christ and are all members of one another (Romans 12: 4-5)
Do you want to know how the Church should function? Just look at your own body. Every part of your body has a specific function. You have hands that can pick things up with, you have feet that can carry your body as you walk. All that is cool, however, your hands or your feet could not do their jobs unless they are connected to your arms and your legs. You have a heart that pumps blood to every part of your body. You have a set of lungs that delivers oxygen into your bloodstream. Both your heart and lungs cooperate with each other, but they would be useless if they were not connected to the rest of your body. You have eyes to see with, ears to hear with, a mouth allows you to eat and taste food and to speak. You have a nose that can smell a rose as well as sour milk, ears that can hear. There are all kinds of organs in the human body, and they must all work together, guided by the head of the body, the brain.
Now, some members are more important than other members are. I suppose that if we had to choose between our right hand and our heart, we would certainly keep our heart. However, we don’t want to be forced to make that choice, do we? Each member is important. While our little finger may not be as important as our left eye, if we were to break it, all of the other parts of the body would cooperate to get it swift medical attention. It’s not just the finger’s problem, it is our problem. We are connected. Each member of our body is important. It is all for one and one for all.
Paul is comparing the mystical body of Christ, the Church, to our human body. Each member has a role, a function, a ministry. Each member is necessary and important. Each member is inter-related to each other member. When we all cooperate under the leadership of the Head, Jesus Christ, the ministry of the local church is powerful and effective.
Verse 5 says that each member belongs to all the others. This is the intimate relationship we have with one another. Look around at each member in whatever church you attend. Look at the people in front of you, behind you, and beside you. They are the Church. They are not all like you. Each one of them has different gifts, different ministries. Unless each of you work together, you are not complete. You need them and they need you. We all need each other in the Church. Not one of you is called to go it alone.
Because all of us are necessary, there is a certain responsibility we have toward one another. With the responsibility comes accountability. If we need one another, then when one of us lays down on the job, the others suffer. We have a responsibility to exercise the gifts and ministries God has given us.
If interested, you can download the entire study of The Letter to Christians at Rome