Acrostic Poem & Dirge
Lamentations is one of the many poems in the Bible (like Psalms or Proverbs). Traditionally, a lament is an emotional statement addressed to God in the hopes that he'll relieve the suffering of the lamenter and intervene to make some changes to the situation that's causing the suffering.
Each of the chapters in Lamentations is written as an acrostic poem. You've probably written or read at least one acrostic in your life. It's just any poem where the first letter of each line spells something out. For example:
Oh so true.
In the case of Lamentations, the author used the alphabet. Well, the alefbet to be exact, since he wrote in Hebrew. Each of the 22 verses in chapters 1, 2, 4, and 5 start with one letter of the 22 letters of the Hebrew alphabet. Chapter 3 still uses the alphabet, but just uses three verses per letter. You can see how it kind of lays out here. Neat, huh?
So why write this whole thing using the ABC's? Well, it might have helped people remember the lines when they didn't have written copies in front of them (which was most of the time 2,500 years ago). But it also could have been a way to fully exhaust the subject. The Poet has explored the destruction of Jerusalem "from A to Z," which means he's said just about everything that needed to be said. (Source HarperCollins Bible Commentary. New York: HarperCollins. 2000. p. 578)
These poems are a bit like a song you might hear at a funeral, which is sometimes called a dirge. Basically, it's just a really, really, sad verse. But unlike a funeral song, this wasn't just written for one person. It's dedicated to the suffering of a whole nation of people. Even the rhythm of the lines sorts of limps which makes it feel like the words are choking or sobbing. (Source HarperCollins Bible Commentary. New York: HarperCollins. 2000. p. 577)