Lines 9-12 Summary

Lines 9-10

'Gainst death and all-oblivious enmity
Shall you pace forth; your praise shall still find room

• Line 9 usually marks the volta, or turn, in Shakespearean sonnets, where the poem switches gears into a new mood, new idea, or new perspective (see more under "Form and Meter"). The change is not as pronounced in Sonnet 55, but it does signal a change from comparison to active engagement. 
• What do we mean by this? Well, in the first two quatrains, the beloved is described as better, but separate from, the other kinds of destruction going down. Monuments crumble, statues topple, but the beloved boy persists in his own happy sonnet-world, untouched by any of this unpleasant stuff 
• In lines 9-10, on the other hand, the boy confronts death and enmity head on. In fact, it's almost as if he's striding out of the poem to meet them. This sonnet has declared war on war and death on death.
• "All-oblivious" here doesn't mean that enmity (a synonym for "war") is some kind of unaware teenager, completely unconcerned with the outside world. What it is oblivious to is human life and art—in other words, it's blind to the beauty and worth of these things and just wants to knock them down.
• But "oblivious" can also mean causing something to be forgotten. If this enmity's all-oblivious, then, it adds another layer of destruction to this nightmare vision: not only will everything be ruined; it will also be totally forgotten.
• Before you go, admire how the "liv" in "oblivious" echoes the other "live"s in the poem in lines 2, 8, and 14. There's more to explore under "Symbols, Wordplay, and Imagery."

Lines 11-12

Even in the eyes of all posterity
That wear this world out to the ending doom.

• Picking up after the semicolon in line 10, we've got a tricky sentence that combines figurative imagery (find room in eyes), unclear syntax (who's wearing out the world exactly?), and some not-so obvious theology (hey there, doom).
• So what's going on? Basically, because of this admiring sonnet, the cute subject will enjoy eternal life and praise as long as this sonnet survives. And how many people will praise him? "All posterity" = everyone. And for how long? Why, just until the end of the world, that's all.
• This speaker is definitely not shy about calculating how many people will end up reading his poem. And given the persistent popularity of Shakespeare's sonnets, it turns out his arrogance was spot on.
• The image of the beloved's praise finding "room" in the eyes of all the sonnet's readers might be a pun on "stanza," which is Italian for "room." In other words, the praise contained in these stanzas, or rooms, is transferred into other rooms (the eyes of readers) as soon as they read the sonnet.
• It's kind of tough figuring out what "that" in line 12 refers to, but the best guess is probably "posterity" in line 11, since it's the closest noun. That would give us this paraphrase: all future generations of the world will eventually wear down the world until it collapses in a heap like a popped balloon.
• "Wear out" is like the weaker version of all the decayed, destructive imagery in lines 1-8. Just as this sonnet makes sure the beloved will escape war and death, it also protects him from the long and boring wasting-away of the world itself.
• That's when the Last Judgment or "ending doom" wraps things up with a rousing final act. In Christian theology, the Last Judgment is like a major trial of everyone's soul. The verdicts: heaven if you're good, and hell if you're bad. In either case, your body gets to be reunited with its soul (yay) and death is over.
• Don't miss the P alliteration of "pace" and "praise" and the almost-rhyme of "shall" and "still" (10).
• We're just keeping your ear as with it as your brain.