For as in one body, etc. The very thing which he had previously said of limiting the wisdom of each according to the measure of faith, he now confirms by a reference to the vocation of the faithful; for we are called for this end, that we may unite together in one body, since Christ has ordained a fellowship and connection between the faithful similar to that which exists between the members of the human body; and as men could not of themselves come together into such an union, he himself becomes the bond of this connection. As then the case is with the human body, so it ought to be with the society of the faithful. By applying this similitude he proves how necessary it is for each to consider what is suitable to his own nature, capacity, and vocation. But though this similitude has various parts, it is yet to be chiefly thus applied to our present subject, -- that as the members of the same body have distinct offices, and all of them are distinct, for no member possesses all powers, nor does it appropriate to itself the offices of others; so God has distributed various gifts to us, by which diversity he has determined the order which he would have to be observed among us, so that every one is to conduct himself according to the measure of his capacity, and not to thrust himself into what peculiarly belongs to others; nor is any one to seek to have all things himself, but to be content with his lot, and willingly to abstain from usurping the offices of others. When, however, he points out in express words the communion which is between us, he at the same time intimates, how much diligence there ought to be in all, so that they may contribute to the common good of the body according to the faculties they possess. [1]

Footnotes

1 - The Apostle pursues this likeness of the human body much more at large in 1-Corinthians 12:12-31. There are two bonds of union; one, which is between the believer and Christ by true faith; and the other, which is between the individual member of a church or a congregation and the rest of the members by a professed faith. It is the latter that is handled by the Apostle, both here and in the Epistle to the Corinthians. -- Ed.

For - This word here denotes a further illustration or proof of what he had just before said. The duty to which he was exhorting the Romans was, not to be unduly exalted or elevated in their own estimation. In order to produce proper humility, he shows them that God has appointed certain orders or grades in the church; that all are useful in their proper place; that we should seek to discharge our duty in our appropriate sphere; and thus that due subordination and order would be observed. To show this, he introduces a beautiful comparison drawn from the human body. There are various members in the human frame; all useful and honorable in their proper place; and all designed to promote the order, and beauty, and harmony of the whole. So the church is one body, consisting of many members, and each is suited to be useful and comely in its proper place. The same comparison he uses with great beauty and force in 1Co. 12:4-31; also Ephesians 4:25; Ephesians 5:30. In that chapter the comparison is carried out to much greater length, and its influence shown with great force.
Many members - Limbs, or parts; feet, hands, eyes, ears, etc.; 1-Corinthians 12:14-15.
In one body - Constituting one body; or united in one, and making one person. Essential to the existence, beauty, and happiness of the one body or person.
The same office - The same use or design; not all appointed for the same thing; one is to see, another to hear, a third to walk with, etc.; 1-Corinthians 12:14-23.

For as we have many members - As the human body consists of many parts, each having its respective office, and all contributing to the perfection and support of the whole; each being indispensably necessary in the place which it occupies, and each equally useful though performing a different function;

(4) For as we have many members in one body, and all members have not the same office:
(4) There are two reasons for the previous precept: the first is because God has not committed everything to be done by every man: and therefore he does backwardly, and unprofitably, and also to the great disservice of others, wearying himself and others, who passes the bounds of his calling: the second is because this diversity and inequality of vocations and gifts results in our being benefitted: seeing that this is therefore instituted and appointed, so that we should be bound one to another. From which it follows that no man ought to be grieved at this, seeing that the use of every private gift is common.

For as we have many members in one body,.... The apostle illustrates what he said last concerning God's dealing to every man the measure of faith, by comparing the church of Christ to an human body, which is but one, and has many members in union with it, and one another; and which are placed in an exact symmetry and proportion, and in proper subserviency to each other, and for the good of the whole:
and all members have not the same office, or "action"; they do not exercise the same function, and perform the same operation, but each that which is peculiar to itself: the eye only sees, but does not hear, nor taste, nor smell; the ear only hears, but neither sees, or does any of the aforesaid things; the palate tastes, the nose smells, the hand handles, the foot walks, and the same may be observed of the other members of the body, which have not the same, but their particular offices, and all and each of them their usefulness.

For as we have many members, &c.--The same diversity and yet unity obtains in the body of Christ, whereof all believers are the several members, as in the natural body.