For we being many are one bread, and one body: for we are all partakers of that one bread. (1 Cor 10:17)
Commenting on the significance of “one bread” (εις αρτος) vis-à-vis the origin and meaning of ecclesiastical union in the celebration of the Eucharist, Eric Svendsen wrote:
what is the point that Paul makes about the bread? Paul goes beyond the mere fact that it is a participation in the body of Christ and in addition, shows its significance for unity. There is one (εις [heis]) loaf of bread in the Lord's Supper. This one loaf, according to Paul, somehow creates unity within the body: οτι εις αρτος, εν σωμα οι πολλοι εσμεν ("because there is one loaf of bread, we who are many are one body"). As if to prevent someone from downplaying the force of οτι (hoti), Paul adds: οι γαρ παντες εκ του ενος αρτου μετεχομεν ("for we all partake of the one loaf of bread"). There can be no mistaking Paul's meaning here, and it is doubtful that the grammar can be taken any other way. Paul believes there is theological significance in the singularity of the loaf of bread. It is important to Paul that there is an expression of unity in the body (not merely a static concept of unity); this is accomplished by all partaking of one loaf of bread. Harris' assertion that the single loaf and single cup "expressively symbolize the unity of believers" is true in itself, but does not go far enough. Paul does not say that we partake of one loaf of bread because we are one body; on the contrary, we are one body because we partake of one loaf of bread. As Wainwright notes, the bread "both signifies and causes churchly unity" (emphasis his). The force of οτι and γαρ together makes it clear that Paul sees the singularity of the loaf as a cause of this unity, not merely its symbol. (Eric D. Svendsen, The Table of the Lord: An Examination of the Setting of the Lords' Supper in the New Testament as an expression of Community [rev ed.; Atlanta: New Testament Restoration Foundation, 1996, 1997], 16)