How we cite our quotes: (line) or, if referencing Looking Glass, (page)
Quote #1
"Beware the Jabberwock, my son
The jaws that bite, the claws that catch! (5-6)
This violence is all in the verbs, here. Most things have jaws, and even little birds have claws, but it's all about what's done with them that counts. Here, the violence isn't happening, but it's posited as imminent or coming. If one were to encounter the Jabberwock, it would catch you and bite you. Because that's what it does. This passage instills fear in the reader because we're scared of bodily harm. Being hurt is no good, and we try to avoid it whenever we can. That caution, combined with the horrific idea of harm coming via something eating us, creates a palpable sense of evil in just two lines.
Quote #2
He took his vorpal sword in hand; (9)
Another "violence is coming!" quote. Here, we have brashness as well. The son doesn't even say anything (that we know of) to the father. He simply picks up his sword. And since we typically don't just brandish weapons around for fun, we assume as readers that his next action is going to be to go hunt down the beast(s) and fight it (or them). So far it's all been implied, but we know something violent is coming. It's just a matter of when.
Quote #3
The Jabberwock, with eyes of flame,
Came whiffling through the tulgey wood,
And burbled as it came! (14-16)
Lots of nonsense words here, but after some parsing, it's clear that the Jabberwock isn't just taking a stroll. He's whiffling, which if you'll recall from our line-by-line analysis, probably means moving very fast. And "eyes of flame." Here's another threat of bodily harm, although this one is a subtler. We associate fire not only with heat, but also (and perhaps more often) with burning and injury. And since eyes are, to use the cliché, the "windows of the soul," and the Jabberwock's eyes are full of fire. A burning, thrashing soul indeed – the motions here are most certainly violent.
Quote #4
One, two! One, two! And through and through
The vorpal blade went snicker-snack! (17-18)
Finally, some actual, combat-style, hand-to-hand violence. This is all we get in the poem – we've got one more quote to come, but it's after the slaying. Perhaps because it was positioned as a book for children, the actual battle in "Jabberwocky" is nearly an afterthought. We have four swings of the blade, and the implication that the blade is going "through" something (which, if you use your imagination is probably pretty gross), and that's nearly it. We also have snicker-snack, the auditory clue that the sword is making contact with flesh. Again, if you use your imagination here, you could probably come up with something downright gory, but the poem isn't going to give it to you – it doesn't want to scare off its youngest readers.
Quote #5
He left it dead, and with its head
He went galumphing back. (19-20)
Thus ends our battle scene. With no evidence of struggle, we have to kind of imagine it, but the outcome is decisive indeed and that the Jabberwock is dead. (Things we don't know that are also interesting to contemplate: whether or not the protagonist was injured, how long the fight lasted, how exactly he killed the monster, etc.) Not only is it dead, but our hero beheads the thing. If you let your imagination do some work, this image is horrific. Again, given the genre of the poem (quasi-children's-lit), it probably isn't reasonable to expect Carroll to outline in gory detail every moment of this violent encounter. But nevertheless, the creature is not only killed, it's dismembered, and its head is almost literally brought back on a platter.