In the narrative of the Conversion of St. Paul, we learn about the the Mystical Body of Christ: the communion of Christians who compose a corporate body. Let’s recall St. Paul’s conversion experience:
But Saul, still breathing threats and murder against the disciples of the Lord, went to the high priest 2 and asked him for letters to the synagogues at Damascus, so that if he found any belonging to the Way, men or women, he might bring them bound to Jerusalem. 3 Now as he journeyed he approached Damascus, and suddenly a light from heaven flashed about him. 4 And he fell to the ground and heard a voice saying to him, "Saul, Saul, why do you persecute me?" 5 And he said, "Who are you, Lord?" And he said, "I am Jesus, whom you are persecuting; 6 but rise and enter the city, and you will be told what you are to do." 7 The men who were traveling with him stood speechless, hearing the voice but seeing no one. 8 Saul arose from the ground; and when his eyes were opened, he could see nothing; so they led him by the hand and brought him into Damascus. 9 And for three days he was without sight, and neither ate nor drank. (Acts 9:1-9)
Here we see Saul (St. Paul’s Hebrew name) persecuting “the disciples of the Lord.” He is persecuting Christians like us. Then Jesus speaks to him; Jesus does not say, “Why are you persecuting my followers.” Rather, Jesus says, “Why do you persecute me?”
Now, consider that when God says a thing is so, then it is so. Here God is referring to the Christians and calling them “me.” From this, we must conclude that we Christians and God are somehow the same thing. How can this be? God is the great God, and I am nothing in comparison. The answer to this puzzle is shocking:
His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence, 4 by which he has granted to us his precious and very great promises, that through these you may escape from the corruption that is in the world because of passion, and become partakers of the divine nature. (2 Pet 1:3-4)
We have become partakers of the divine nature. God has shared His nature with us. This is remarkable, fantastic, almost unbelievable were it not spelled out in Scripture so clearly. Our baptism gave us sanctifying grace and grace is just a word that means "gift." This gift is the sharing of God’s nature with us.
We know that there are three Persons in God and these Three are one, that is, their communion is so perfect that they are both three and one at the same time. This communion is an aspect of the divine nature, which we now share. As the Father, the Son and the Holy Spirit are united with each other, so we are united with Them. This, I believe, is what Jesus means when he identifies His disciples with Himself.
St. Paul, who heard this teaching from Jesus Himself in this most extraordinary conversion event, is our apostle of the Mystical Body of Christ. He says,
For just as the body is one and has many members, and all the members of the body, though many, are one body, so it is with Christ. 13 For by one Spirit we were all baptized into one body -- Jews or Greeks, slaves or free -- and all were made to drink of one Spirit… 27 Now you are the body of Christ and individually members of it. (1 Cor 12:12-13,27)
In this passage and so many others, St. Paul compares us to a human body of which Christ is the head. Each of us individually is a member of this body. He teaches us that, as we are members and as members of bodies have purposes, so each of us has a purpose which is different from the other members. Put another way, each of us has gifts that we should share with the Church; my gifts are different from yours, yet all are necessary. This body analogy used by St. Paul to teach us about our communion with God and each other is referred to as the Mystical Body of Christ, which is the Church.
This doctrine is food for endless contemplation. I would like, however, to focus on one point. In the above passage, but a few verses on, St. Paul notes that, though each of us has a specific gift, those with the lowliest gifts are actually providing the greatest benefit to the Church. Using this text, Pope Pius XII notes:
For as the Apostle with good reason admonishes us: "Those that seem the more feeble members of the Body are more necessary; and those that we think the less honorable members of the Body, we surround with more abundant honor." (1 Cor 12:22-23) Conscious of the obligations of Our high office We deem it necessary to reiterate this grave statement today, when to Our profound grief We see at times the deformed, the insane, and those suffering from hereditary disease deprived of their lives, as though they were a useless burden to Society; and this procedure is hailed by some as a manifestation of human progress, and as something that is entirely in accordance with the common good. Yet who that is possessed of sound judgment does not recognize that this not only violates the natural and the divine law  written in the heart of every man, but that it outrages the noblest instincts of humanity? The blood of these unfortunate victims who are all the dearer to our Redeemer because they are deserving of greater pity, "cries to God from the earth." (Mystici Corporus Christi, 94, Pope Pius XII)
There are members of this great Body who seem, in the eyes of the world, to be useless burdens. Yet, these are the souls who are the most valuable to this Body. We who feel we are doing great things for God by our works, by our service and by our “time, talents and treasures” are overshadowed by those who suffer, the weak and the poor. This puts my own gifts and works in proper perspective, and I am humbled. It is yet another example of where the world gets it backwards: the world classifies the sick and the weak as a useless burden and classifies me as productive and useful. It is the poor and the weak to whom I am indebted for their profound value to the Church.