Book 4 of 4 - External Means by which God Invites Us into the Society of Christ and Holds Us Therein
Chapter 17 - The Lord's Supper; what it brings to us
38-46 - Miscellaneous points
38. The Supper implies mutual love
The bread pictures unity, as many grains are baked indistinguishably into one loaf. "The Lord so communicated His body to us there that He is made completely one with us and we with Him." If we disagree with a brother, we disagree with Christ. If we love Christ, we must love His people.
39. The Supper can't exist apart from the Word
Promises spoken at the supper aren't directed to the elements, in consecration, but to the people receiving them. The minister should not be silent when administering the supper: "silence involves abuse and fault."
40. Unworthily partaking of the Sacrament
The Supper becomes "deadly poison" for the one who tramples upon it. The elements, entering a corrupt soul, "cast it down with a greater ruin." They "foully defile [the Lord's body and blood] with sacrilegious impiety." Defiling the Lord's Table is possible.