So, when is it appropriate to quote? One occasion is when the language of the text itself is a factor in your argument. For instance, if you were writing about Mark Twain's Huckleberry Finn to showcase the racial barriers between characters, a summary of a line would simply not create the same effect as say quoting "'NOW, old Jim, you're a free man again, and I bet you won't ever be a slave no more.' 'En a mighty good job it wuz, too, Huck. It 'uz planned beautiful, en it 'uz done beautiful; en dey ain't NOBODY kin git up a plan dat's mo' mixed-up en splendid den what dat one was'" (38-39). Here, Jim, the runaway slave, is juxtaposed with the title character. Specifically, Twain's use of phonetic vernacular exemplifies the racial and cultural barriers between the two characters. In this case, you see, a summary of the line would simply not create the same effect.
Other times "to quote:"
- If the text holds historical value
- If a particular line or section jumps out at you
- If the line(s) is essential to the storyline, argument, character development, or context as explored in your essay