"The church is the body of Christ, so we are the only 'hands' He has to do His work;" or, "If one helps the church, that is helping Christ;" or, "Splitting the church is the same as driving the spear into His body on the cross." These and more like them are common sayings among "us," but I wonder how much thought "we" have given to what we are saying.
Questions one: WHAT church, universal or local, is the body of Christ? Passages usually cited (Eph. 1:23 and Col. 1:18) clearly refer to the universal church or saints in the aggregate. In 1 Cor. 12:13 "baptized into one body" refers to universal church, for we are "baptized into Christ" (Gal. 3:27), not into a local church. Some say vs. 27 "Now ye are the body..." refers to the local church at Corinth, but the language doesn't necessitate that. Were the "apostles, prophets, etc.," of vs. 28, all in Corinth; or was he not saying "ye" saints are a part of the (universal) church, in which all these are found? Surely so!
Question two: HOW are we His body? Obviously, figuratively; i.e., saints in the aggregate are likened to a physical body. But this means the point of likeness is limited by context and we have no right to extend the figure beyond the use made in context. For example: 1 Cor. 12:12-f. uses the body to teach working together, each member as equipped and suited (vs. 24-f). Christ as "head" is not in this figure. Members are ear, eye, etc.
In passages that emphasize Christ as "head" of the body, corporate body may be the idea, although no violence is done in thinking physical body. In Eph. 1:23 "the fullness of him that filleth all in all" emphasizes what He does for us, not what we do for Him. And in Eph. 3:6 Jews and Gentiles are "joint-heirs" a "joint-body" and also "joint-sharers" (see Marshall trsl.). Here "body" refers to the Messianic community of saints (Meyer).
In Romans 6: "body of sin" applies the figure in yet a different way. Here it refers to our past sinful life, considered as a "whole." Or in Col. 2:17 "body" (the real substance) is contrastd with "shadow." We only cite these places to show that "body" may have many applications—all beginning with the same word but extended by metaphor. However the Holy Spirit saw fit to use the figure, we must seek to determine that usage by study of the context, and then stop there.
When we see that "body of Christ" refers to the universal church, or to all saints in the aggregate, we can see why Moses E. Lard once argued the "body of Christ" can not be split. He knew congregations could split, but the Lord's (true and faithful) people are united. In a local church of 300, 285 may go their own way, keep the building, and "cast out" 15 true followers of Christ (3 Jn. 9-10). The Lord's body did not split. It stayed together, and met elsewhere for worship. But the 285 could be the true church, but if so it is because they stay faithful to the Lord, not because they are more numerous, or have "dubs" on "the Lord's