All my readers who have sung the “Alleluia” Chorus from the Messiah raise a hand, forefoot, or paw. All those who have heard (because you never did it, I’m sure) an impromptu solo in the next-to-last measure keep your appendage up. Thank you. You can lower them.
The caesura, or sometimes called a “grand pause” is a technique composers use to build or maintain tension in a piece of music. It is also one of the best opportunities for an instrumentalist or vocalist to have a solo without the need of practicing or trying out. This is generally not a good thing.
The rest prior to the last “alleluia” in the “Alleluia Chorus” may be the most (in)famous grand pause in choral music, but it’s not the only one. Two other choruses in the Messiah use the technique, and I’ve sung more recent compositions where that is used. And you can tell who is watching* the conductor, or who has actually listened to the recording and knows what’s not supposed to be heard at that place.
When seen in the wild:
If you are a soloist without a conductor, you may pause as long as you so choose, provided your accompanist knows what to do. The rest of us really ought to be watching the conductor.
The longest and most tension-filled grand pause I have heard is in the Mormon Tabernacle Choir’s recording of Moses Hogan’s “Battle of Jericho” on Come Thou Fount of Every Blessing. They just hold the pause and hold the pause and you are aching for the chord to resolve… and then it does. It’s only three and a half seconds, but wow, is it long.
[They take it too fast in this recording, in my opinion, but they are good enough to do it without a complete runaway. The CD is a whisker bit slower.]
*How many choir directors does it take to change a light bulb?
No one knows, because no one’s ever watched a choir director.