This is where all of the games are discussed.
That was a lamentable FJ! for me. Jeremiad is not (OK - was not) in my vocabulary, so that wasn't a help. Longest book? Isn't that Psalms? (Quick sanity check after the fact - Jeremiah is 130 pages in my Bible, Psalms is 180. Not the measurement specified in the clue, of course.) But Psalms doesn't fit the rest of the clue. Must be something else - lots of white space on the page in Psalms. I went straight to trying to fit the vocabulary exercise rather than think about book length. Isaiah? It's long, but doesn't ring any vocabulary bells. At the last second, I went with Lamentations just to have something that at least could fit part of the clue. In hindsight, I should have focused on book length instead of trying to figure it out from the vocabulary side. That would quickly whittle things down to just a few reasonable guesses, improving the chance of a random guess between them getting lucky.