The present translation of Form B is a bit off… but here’s a bit about the upcoming translation:
In Form B, the priest and the congregation speak two prayers for mercy from Scripture. First, the priest says “Have mercy on us, O Lord,” to which we respond “For we have sinned against you.”
The priest speaks the first half of Baruch 3:2, and we respond with the second half. This profession of guilt reminds us of our need to live holy lives “worthy of the calling to which you have been called.” (Eph. 4:1) The plea for mercy reminds us of how ready God is to bestow the abundance of His gracious mercy upon us.
Then the priest says “Show us, O Lord, your mercy,” to which we respond, “And grant us your salvation.”
Again, the priest begins Psalm 85:7 and we complete it. We do not simply ask the Lord for mercy, but for His salvation. The Lord Jesus did not come to earth simply to forgive our sins, but to “lead us, with our sins forgiven, to eternal life,” as the priest says in the prayer at the end of the Penitential Rite. Through Jesus Christ, we have not only the forgiveness of our sins, but the hope of eternal salvation.