Gospel confession in worship
There is a pattern of sacrifice in OT: first sin, whole ascension, and peace offerings. We do not sacrifice animals anymore, but the pattern still holds. The sin sacrifice, where the focus is on the blood poured out, and the body is brought outside the camp. This focuses on the death of Christ for our sin. So we confess our sin and appeal to the cross. The blood makes atonement, and this part of the service is all about atonement. This keeps the service gospel centered, even if the sermon doesn’t mention the atonement of Christ. There must be death for our sin, so Christ’s blood is displayed. He is the sacrificial lamb. We have died with Him, buried with Him in baptism Rom 6 says. So we come to God under the covering and protection of Christ’s blood.