As one writer aptly put it, one of the reasons we go to church is to learn how to love people we don’t like very much. And the testing point of this is here, at this Table. When you come, you are coming as a reconciled people, and this means that you are not only reconciled to God, but also to one another. You confess your sins to God at the beginning of the service (or whenever it is appropriate to do so), and you should also have made anything right with your neighbor if there is anything between you.
This does not mean that you have to become fishing buddies with everybody—you cannot be equally close to everyone. Jesus called the seventy, and out of the seventy, He chose twelve, and out of the twelve He was closer to three, and out of that three, He was closest to one. If Jesus had a best friend, there is no reason you cannot be closer to some than others.
So in what sense is this meal a testing point? If there is some sort of friction between you and another, or if you have clashed, put it right, but things are still tense, if your relationship is okay but the situation is not, it must gladden your heart that this other person is coming to the Table. And no, it must not be because you think that the other person really needs it. No, you must be delighted to be there together because you both need it. It must be an occasional of joy to you that the Spirit is in the process of knitting you together with this difficult person. It may be a help for you to recognize that He is doing the same thing for the other person—he also is being knit together with a difficult person.