In that now famous quote by Kierkegaard, he stresses that the members of the congregation are the "performers" with God as the "audience" (and not the congregation as the audience to performers on the platform). In other words, worship is something done by God's people not for God's people.
Congregational participation in corporate worship is in fact a direct application of the biblical doctrine of (and the Reformation re-emphasis on) the priesthood of all believers: unlike Israel, we have no priestly mediators who perform the rituals of worship on our behalf - our great High Priest has, by the offering of Himself as a sacrifice, opened forever the way for us through the veil and into the presence of God (Hebrews 8--10). Thus congregational participation in worship is in itself a powerful testimony to the nature of the New Covenant.
The Singing Congregation
Music is a gift of God ideally suited for the praise of the Creator -- in heaven and in the church on earth. The congregation is, as William Rayborn has pointed out, the most important singing group in the church (the wonderful ministry of the choir notwithstanding). Following are some ways the congregation can be brought into a greater participatory role in worship through song:
Give them credit. Almost all of them can read! Therefore, announcing every hymn number found in the bulletin, or every song title projected on the wall, is almost an insult to the intelligence of the worshiper, and certainly can detract from a worshipful atmosphere. That is not to say that thoughtful words of introduction can't sometimes set the tone in an effective way; but a rote lead-in that is always the same would be better left out. The bulletin or projection tells the people what to sing; the instrumental introduction tells them in what key and tempo to sing; and the song leader shows them when to sing - - so why not just let them start singing?
Let the choir coach. Use the choir to sing through a song that is unfamiliar, then let the congregation join in the second time. If the tune is not too difficult, it is surprising how quickly the average group can pick up on it.
Let the choir model. Expressions of joy or wonder, enthusiasm in singing, and an obvious heart for worship go a long way towards motivating the congregation. In this way the choir members truly serve as worship leaders (and fulfill Kierkegaard's view of them as "prompters" for the audience "performers").
Use hymns creatively. There's no law that says all verses of a hymn must be used every time. In fact, if a theme is being developed, very often only one or two verses will pertain to that theme. (Count von Zinsendorf of the Moravian Brethren was known for stringing together individual verses of various hymns to develop a theme.) For example, the first verses of both "Praise to the Lord, the Almighty" and "Crown Him with Many Crowns" refer to Christ as King (and the other verses do not), and so could be effectively incorporated into a service celebrating Jesus as King of Kings. Similarly, verse 2 of "Joyful, Joyful We Adore Thee" praises God for His works of creation in a way that the other verses do not, making it appropriate to use that verse alone in a service dealing with God as Creator. If every hymn is not sung in its entirety, then when one is done full-scale (all of its verses, perhaps with modulations and/or choral descants) it will stand out more and be a more effective worship vehicle.
Try changing the tempo and/or dynamic range of a hymn. Taking a majestic praise hymn and giving it a contemplative, peaceful setting can greatly enhance the congregation's appreciation of the text (for example, the first and last verses of "Praise to the Lord, the Almighty"). More contemporary harmonization's of some of these hymns may be found as well, which when combined with a slower setting produce a sort of praise chorus out of a verse of a hymn like "All Creatures of Our God and King." In fact, an effective way to add unity and coherence to a service can be to use such a verse at the beginning, and then to climax at the end of the worship time by singing all of the verses of the same hymn in its traditional majestic setting.
It is remarkable how taking well-known texts and singing them in unfamiliar ways can make those texts come alive (even to young people). Those great texts deserve to be savored and reflected on, not just sung in a lifeless, rote manner.
It has often been pointed out that many of the settings of hymnbooks are pitched too high for comfortable singing by untrained voices. It is worth the trouble to transpose them down (by hand or using a music notation program) if your accompanist is not comfortable transposing by sight. (Down a Key, published by Kevin Mayhew Limited, contains lower settings of standard hymns.)
Use choruses judiciously. Long strings of contextually unrelated choruses are not conducive to reflective worship, for there is no time to linger on a single aspect of God's nature or work; but neither should a single chorus be repeated more than once as a general rule. Choruses should be chosen not just for their key or tempo, but to make a particular contribution to a theme or a mood of worship.
Mix hymns and choruses. If a theme gives a reason for being for the songs selected, the juxtaposition of hymns and choruses need not be unduly jarring.
Sing antiphonally with the choir. "Antiphonal Praise" by Steve Green is an excellent example of a worshipful song where line by line may be sung first by the choir or vocal ensemble, then echoed by the congregation.
Sing canons (rounds). Rounds are the simplest form of polyphony, allowing even a musically untrained congregation to sing in harmony. "Seek Ye First," "Behold, What Manner of Love," and "You Are My Hiding Place" are all familiar two-part rounds. With the proper arm motions (bringing in one-half of the congregation at a time) and with the support of the choir or vocal ensemble, these rounds may actually be sung without prior verbal instructions-- thus allowing them to occur naturally within the flow of the service.
Recognize the beauty and power of a cappella singing. Used sparingly, a cappella singing can be enormously moving. The choir or vocal group can add the harmony while most of the congregation sings the melody.
An accompanied chorus of "I Love You, Lord" at a meditative point in the service can be overwhelming, as can be the last verse of "Fairest Lord Jesus." The refrain of "And Can It Be" ("Amazing Love . . .") is a lovely congregational response to a choral anthem which deals with the atoning work of Christ.
A cappella singing can also be used climatically. When singing all verses of "The Solid Rock," building up to an unaccompanied refrain on the last verse can be thrilling. Equally exciting is to sing the first verse of "I Stand Amazed" in unison, crescendoing over a pedal on the dominant until breaking forth into the refrain unaccompanied (with the choir supporting in parts).
The Speaking Congregation
The spoken word is likewise a legitimate vehicle for the congregation to express itself in worship. The reciting of one of the creeds is a weekly practice in some churches; this repetition can (though need not) become rote, so most non-liturgical churches have eschewed the practice. But the mere fact that it is not done regularly may make it an effective element to use on occasion. Certainly the theology of the great creeds are solid, deep, and comprehensive. Their relative unfamiliarity in free churches can lend to their being used as effective doctrinal confessions and expressions of worship. The Te Deum may likewise be used; also some devotional writings may lend themselves to being read in unison or responsively.
Of course, the Word of God is the richest resource for congregational recitation in worship. Some churches with pew Bibles or with a single-translation tradition like to read Scripture passages out loud together; others confine themselves to the responsive readings found in the book of most hymnals.
It is well worth the effort to put together "original" responsive readings which incorporate a variety of Scripture texts. This is a wonderful way to help develop a theme in worship. For example, a responsive reading including Psalm 2:1-3; Isaiah 40:23-24,15; Psalm 2:10-11; 47:8; 46:10 can add a healthy biblical perspective on God's sovereignty over the nations to a patriotically oriented service (Independence Day, etc.). And a responsive reading is a great way to pull together many related texts (Genesis 2:7; Job 10:10-11; Isaiah 44:24; Psalms 139:13-16; 119:7) to instruct and encourage God's people on Sanctity of Human Life Sunday.
Such readings are not too difficult to develop with the use of a concordance (especially a computer concordance which allows for searches of pairings of specific words).
The standard back-and-forth between leader and congregation in responsive readings is usually adequate; for it is the content which is of paramount importance. However, sometimes a little variety may be incorporated by giving lines to men and women, to the left side and right side, or by using the choir as a third group alternating with the leader and the congregation.
Conclusion
It is imperative that the members of our congregations leave, not just having attended a worship service, but having worshiped. It is worth all the creativity and effort we can muster in an attempt to lovingly draw the people of God into meaningful participation in expressing praise to the God of their salvation.
Experiencing Worship, The Study