How should a service of Christian worship be ended? There are several options, and it's worth laying them out as a prelude to considering the respective merits of each. As we'll see, a given liturgical element could fall into more than one of the following categories.
1. Blessing. Spoken by the Minister to the congregation.
For example, "The LORD bless you and keep you; the LORD make his face to shine upon you and be gracious to you; the LORD lift up his countenance upon you and give you peace" (Num 6:24-26).
Notice that this is not a prayer. The Minister does not petition the LORD ("May the LORD bless you..."); rather, he proclaims and declares the LORD's blessing upon the people.
2. Doxology. Declaration of praise to God, spoken either by the Minister or the whole congregation.
For example, "Glory be to the Father, and the the Son, and to the Holy Spirit. Amen!"
This is a prayer in the sense that any praise is prayer - it's a plea that God should so act as to bring glory to himself.
3. Prayer. By the Minister alone or the congregation together. Almost any text could be used.
4. The grace. This familiar text from 2 Cor 13:14 is best considered in a category of its own, not least because it can be employed in one of two different forms, which fall respectively into categories 3 and 1 above.
The grace is very often spoken by the whole congregation as a prayer (category 3), "May the grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all. Amen." Here the whole congregation addresses God, which makes the practice of looking around at one another somewhat incongruous.
However, when the grace appears in Scripture, it takes the form of a blessing (category 1). No "may" appears at the beginning; instead it is spoken by the apostle Paul to declare God's blessing on the congregation: "The grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all. Amen." In the context, the final "Amen" is perhaps best spoken by the whole congregation, as an wholehearted declaration of assent to the
It's slightly odd that some congregation use the first of these (category 3, a prayer) while looking around at one another. It would make more sense to use the second of these forms (category 1, blessing) while doing this, since then the words could be understood within the framework of the priesthood of all believers, in the sense that the members of the congregation declare God's blessings upon one another.
5. Commissioning. An exhortation to action, most likely spoken by the Minister to the congregation, though conceivably spoken by the congregation to one another.
For example, "All authority in heaven and on earth has been given to Jesus Christ. Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that Jesus has commanded you. And behold, he is with you always, to the end of the age. Amen!" (from Mt 28:18-20).
This is neither a prayer nor a blessing, being directed to the conregation, not to God. Perhaps for this reason it is particularly fitting for the end of the service if spoke by the Minister on behalf of the Lord to his bride as they are sent out into the world.
6. Other Scripture reading. This final option covers all the other options, and is perhaps the most common in many contexts. A climactic, resounding text is chosen (Jude 24-25 or Hebrews 13:20-21, for example, or perhaps a text from the Psalms or the Prophets), which may be a prayer or an exhortation or something else, but is used principally because of the rhetorical effect of leaving the congregation with such stirring words ringing in the ears as the service ends.