12.For as the body is one He now derives a similitude from the human body, which he makes use of also in Romans 12:4; but it is for a different purpose, as I have already stated above. In that passage, he exhorts every one to be satisfied with his own calling, and not to invade another’s territory; as ambition, curiosity, or some other disposition, induces many to take in hand more than is expedient. Here, however, he exhorts believers to cleave to each other in a mutual distribution of gifts, as they were not conferred upon them by God that every one should enjoy his own separately, but that one should help another. It is usual, however, for any society of men, or congregation, to be called a body, as one city constitutes a body, and so, in like manner, one senate, and one people. Monenius Agrippa, (747) too, in ancient times, when desirous to conciliate the Roman people, when at variance with the senate, made use of an apologue, not very unlike the doctrine of Paul here. (748) Among Christians, however, the case is very different; for they do not constitute a mere political body, but are the spiritual and mystical body of Christ, as Paul himself afterwards adds. (1 Corinthians 12:27.) The meaning therefore is — “Though the members of the body are various, and have different functions, they are, nevertheless, linked together in such a manner that they coalesce in one. (749) We, accordingly, who are members of Christ, although we are endowed with various gifts, ought, notwithstanding, to have an eye to that connection which we have in Christ.”
So also is Christ The name of Christ is used here instead of the Church, because the similitude was intended to apply not to God’s only-begotten Son, but to us. It is a passage that is full of choice consolation, inasmuch as he calls the Church Christ; for Christ (750) confers upon us this honor — that he is willing to be esteemed and recognised, not in himself merely, but also in his members. Hence the same Apostle says elsewhere, (Ephesians 1:23,) that the Church is his completion, (751) as though he would, if separated from his members, be incomplete. And certainly, as Augustine elegantly expresses himself in one part of his writings —
“Since we are in Christ a fruit-bearing vine, what are we out of him but dry twigs?” (John 15:4.)
In this, then, our consolation lies — that, as he and the Father are one, so we are one with him. Hence it is that his name is applied to us.