The apostle Paul teaches us that we are all one loaf (1 Cor. 10:17). We are one body, one loaf, one congregation. We symbolize this by symbolically partaking of one loaf. Now if it happens that we have more saints gathered than can be fed by one loaf, no matter. The Lord once took five loaves to feed the multitude, so we shouldn’t worry about it.
At the same time, there are other actions that are filled with symbolic meaning, they are freighted with meaning, and we cannot just arbitrarily say that they are not a big deal. Make sure you understand that the Bible makes a big deal out of eating together, and the unity this displays.
There are two common ways of disrupting this—one is by dividing the guest list, and the other is by dividing the menu. The first says that you may come, and you may not, and this—outside of Christ, or outside the lawful discipline of the church—is a huge deal. The apostle Paul confronted Peter over just this thing at Antioch. What some might have described as just the seating arrangements at the potluck, the apostle Paul took as an assault on the gospel. So if you divide the guest list here racially, or tribally, or with regard to income bracket, it is an awful sin.
Another way of disrupting fellowship is by inviting everybody, and dividing the menu. Paul says here that we are making a statement that we are one body because we have one food—in this case, bread and wine. We are Christians, which means we must not be picky eaters. So come, and welcome, to Jesus Christ.