Psalm 80's thrice-repeated refrain (vv. 3, 7, 19) is a clue both to the psalm's liturgical origins and its driving theological concern.
The refrain indicates that the poem finds its origins as a corporate prayer, with the congregation or a choir intoning the refrain. [NOTE: For worshiping communities that sing the psalms responsively, please note that worship planners would be well advised to take pains to have the congregation sing the refrain. If one simply plows ahead in an every-other-verse fashion, the refrain might be found on the lips of the singer of "Part A" in vv. 3 and 7, but on the lips of "Part B" in v. 19. Ugh!] The petition in the psalm's second verse, "Stir up your might, and come," is the source for prayer of the day for the First Sunday in Advent: "Stir up your power, Lord Christ, and come."
In terms of the psalm's overriding theological concern, the refrain shows that the psalm is a prayer for deliverance: "Restore us, O God!" The psalm is vague as to what crisis may have originally precipitated the plea. Perhaps it was the Babylonian exile or some other national humiliation. Or perhaps the psalm was composed to be performed annually as part of a national worship commemoration. This is not clear, but the surrounding doubt is actually a positive--it allows the prayer to be sung by any community undergoing crisis, or even by a thriving community on behalf of others who are suffering.
Three verbs dominate the refrain: Restore (Hebrew shub), shine ('ur), save (yashab). The psalm exploits a dual meaning of the first word (shub). In the refrain, the word means "restore," and is a plea that God would change the circumstances of the people. But in v. 14, the word means "turn," or "repent" (cf. Psalm 90:13), and is a plea for God to change God's will concerning the people's situation. The poetic play on these two meanings of the word amounts to a faith assertion by the community--the solution to the people's situation rests in the heart of God. The people cannot change their own circumstances, but God can--simply by willing that the situation be reversed.
Similarly, the plea that God "let your face shine" is plea for God's favor to radiate on the people, like the sun bathes the earth in light. In the psalms, God's disfavor is often pictured as God hiding God's face, or turning away from the community. Most people of faith are familiar with the words of the benediction: "May God's face shine on you" (cf. Numbers 6:25). The plea here is a prayer for the very thing that is promised in the benediction: God's shining forth in deliverance and blessing.
One more aspect of the refrain is worth mentioning. The refrain builds in intensity each time it occurs, by adding to God's name, moving from the more generic "God" to the more proper and personal "O Lord God of hosts":
This building up of intensity has the effect of turning up the volume on and urgency of the people's desperate cry for help.
The psalm mixes two metaphors for God's relationship with the people. Mr. Fox, my high school English professor, would not have approved of such mixing, but in this case the two dominant metaphors create a rich prayer for help. The first metaphor is of God as the "Shepherd of Israel" (a title known only here in the Old Testament) and the people as God's "flock." The use of this metaphor continues a theme introduced in Psalms 78 and 79. Psalm 78 described the Davidic kings as the shepherds of God's sheep (v. 71). Psalm 79 prayed for God to tend "your people, the sheep of your pasture" (v. 13). Psalm 80 culminates this theme by calling God the Shepherd of Israel. This confession of faith cuts with both a positive and a negative edge. Positively, it asserts that God has the fidelity and integrity to guide Israel through the shadow of the valley of death. Negatively, it asserts that all the other forces trying to claim lordship of God's people (whether emperors, kings, or even religious leaders) are not the true leaders of the people (because they lack both the fidelity and integrity of God).
The second metaphor this psalm employs for the relationship between God and people is the image of the vine and gardener. The metaphor is introduced in vv. 8-13, which the lectionary unfortunately cuts. (These verses should at least be reviewed by one preaching on this text, and the preacher may find it helpful to "restore" them.) Similar to Isaiah's famous parable of the vineyard in Isaiah 5, Psalm 80 recalls God's history of faithful love by making the analogy between that history and a gardener planting a vineyard. But while Isaiah wanted to spur the people repent, the psalmist sought to spur God to repent: "Turn again, O God of hosts; look down from heaven, and see; have regard for this vine, the stock that your right hand planted" (vv. 14-15).
The rhetorical strategy in Isaiah 5 (or Micah 6) has the parental God saying to the rebellious children, "After all the faithful love that I have shown you, why are you rebelling against me?" Here, the rhetorical strategy has the suffering children saying to the parental God, "After all the faithful love that you have shown us, why are you allowing us to suffer?"
The psalm closes with the people vowing to continue to "call on your name." This promise then leads to the last occurrence of the refrain, which as noted above, employs the most personal and intense form of God's name in the psalm: "O LORD God of hosts." God's "name" is a shorthand formula for the relationship between God and God's people. God gave the people the name so they could call upon him in prayer, praise, and thanksgiving, and so that they would bear God's name in their mission to love, bless, and save the nations.