Brand New - Seventy Times Seven Lyrics Meaning

(This is pretty much what everyone else above has said in one big post with a little extra thrown in)

the song is most definitely about John sleeping with Jesse's girlfriend

The first verse is mostly, what I feel to be, the background to the story and how he feels at that point:

"Back in school they never taught us what we needed to know,
like how to deal with despair, or someone breaking your heart.
For twelve years I've held it all together but a night like this is begging to pull me apart.
I played it quiet, left you deep in conversation.
I felt uncool and hung out around the kitchen.
I remember I kept thinking that I know you never would,
and now I know I want to kill you like only a best friend could"

a lot of past tense terms in there which shows its most likely a dresponse which was as near to jesse finding out as possible.

The chorus:

"Everyone's caught on to everything you do
Everyone's caught on to."

is telling us that he (john) has been found out and everyone knows what he done

The second verse seems to be another response except this time its after he found out, maybe a day or two, he is now sad and upset but then angry which leads onto - arguably - the most hate filled lyrics in history

"As if this happening wasn't enough I got to go
and write a song just to remind myself how bad it sucked.
Ignore the sun, the cover's over my head.
I wrote a message on my pillow that says, "Jesse, stay asleep in bed."
So don't apologize. I hope you choke and die.
Search your cell for something with which to hang yourself.
They say you need to pray if you want to go to heaven
but they don't tell you what to say when your whole life has gone to hell."

The lines "how bad it sucked" and "ignore the sun, covers over my head" shows us that he is sad and upset but from there its the angst that becomes prominent. "Dont apologize - I hope you choke and die", "something which to hang yourself" and "your whole life has gone to hell" is all anger filled showing his rage.

The next chorus has the lines:

"And I can't let you, let me down again"

repeated throughout the main chorus telling us that he doesn't feel him and John could be friends again, although they have now made up.

and its after the second chorus when his strong hated comes out:

"So, is that what you call a getaway?
Tell me what you got away with.
Cause I've seen more spine in jellyfish.
I've seen more guts in eleven-year-old kids.
Have another drink and drive yourself home.
I hope there's ice on all the roads.
And you can think of me when you forget your seatbelt,
and again when your head goes through the windshield.

And is that what you call tact?
You're as subtle as a brick in the small of my back.
So let's end this call, and end this conversation.
and is that what you call a getaway?
well tell me what you got away with.
cause you left the frays from the ties you severed
when you say best friends means friends forever

So, is that what you call a getaway?
Well tell me what you got away with.
Cause I've seen more spine in jellyfish.
I've seen more guts in eleven-year-old kids.
Have another drink and drive yourself home.
I hope there's ice on all the roads.
And you can think of me when you forget your seatbelt,
and again when your head goes through the windshield."

I don't think any analysis is needed here as it is pretty straight forward what he is saying, and it seems more than likeky that the lines:

"And is that what you call tact?
You're as subtle as a brick in the small of my back.
So let's end this call, and end this conversation."

were said y Jesse in a call to John but I've been told they are in a Morrissey song, which would also explain it, as Morrissey is a big influence on Jesse.

the song ends with another chorus with "And I can't let you, let me down again" screamed out by Jesse.