The Confessional Address in the title was something we as a congregation heard at the start of the service. If you have a Lutheran Service Book you can see one very much like it on pg. 290. These things as the sermon will say used to be standard in communion services. They would be prior to the Lord’s prayer and remind all what and why we are doing in the Lord’s Supper. Seeing as the entire point of Maundy Thursday is to receive Christ’s mandate, whether that is taken as “love one another” or “do this in remembrance” it seemed a good liturgy to use and understand.