Although optional in 1979, the Daily Office in the 2019 Prayer Book ends with a pair of sentences. “Let us bless the Lord. / Thanks be to God.” is a final doxology, our last word of praise offered to God. “The grace of our Lord Jesus Christ… be with us all evermore” is a final benediction, God’s last word to us. Together, they form a “goodbye” in both directions between the congregation and our Lord, much like the Blessing and Dismissal at the end of the Communion liturgy. The option of Ephesians 3:20-21, however, tips the closing balance in favor of doxology.
Officiant: Let us bless the Lord.
People: Thanks be to God.
The dialogue (or versicle and response) was added in the 1979 Prayer Book, drawn from ancient Gelasian and Roman Office liturgies. It functions in the same way as the Dismissal at the end of the Communion service, which was also first introduced to the Prayer Book tradition in 1979. Both were optional in that edition, but now this dialogue has been fully adopted as a standard part of the the Daily Office liturgy.
What follows is “the grace” taken from 2 Corinthians 13:14. This is functionally like a blessing, or a benediction, used to close the Daily Office since 1662, and the Litany since 1559. Like the 1979 Book, however, our Prayer Book offers Romans 15:13 and Ephesians 3:20-21 as alternatives. The first is also a benediction, but not explicitly trinitarian; the latter is a doxology, rather than a benediction.