Stanzas 3-4 Summary

Get out the microscope, because we’re going through this poem line-by-line.

"I shot him dead because—
Because he was my foe,

In case we hadn't figured it out already, the speaker tells us that he shot the guy because he was his foe, or enemy.
The repeated use of because and his repetition of the fact that he shot this man make us think that the speaker is trying to come up with a reason or an explanation for why he killed the other dude.
He might even be rationalizing the whole awful event to himself, but he's certainly not doing a bang-up job of it if you ask Shmoop. The guy's stumbling over his words.
This long pause and the repetition of because suggests doubt, confusion, and hesitation. So while he seems pretty clear on the whole I-shot-this-guy-because-he-was-my-enemy thing, his mannerisms make us think he's not so sure.
After all, who's to say this guy really was his foe. Since he's an infantry man, we're betting those military hot shot head honchos told him who's friend and who's foe. But, really, why do they get to make that call?
It's entirely possible that our speaker might be struggling with some of these Big Questions. But we can't know for sure—we're hearing his spoken words, not his thoughts.

Just so: my foe of course he was;
That's clear enough; although

Sounds like our speaker is still trying to convince himself of why he shot this man in war. Of course he was my foe. Right guys? Right?Check out the weird jumbling effect in line 11. Suddenly the speaker launches into Yoda-speak when he says "my foe of course he was."
Maybe this reordering is to help the assonance on O stand out, but the poetic inversion of the words makes us feel like the speaker is struggling to put the sentence together. In fact, it almost sounds like he's talking to himself here, muttering the words to make himself believe.
But all he's really doing here is saying the same thing over and over again. We still don't know why he thinks this dead man was his foe. In fact, we have no way of knowing what war these guys were fighting, what the war was about, or whose side they each were on.
And maybe that's precisely the point.
The last word of this stanza packs quite the punch, don't you think? This whole time he's been rationalizing the death of this man he shot, and now, lingering at the end of the line, there's this one little word: "although." It's enjambed with the stanza that follows, so we're left hanging about what he's thinking.
But we know that whatever it is, it's going to contradict the idea that this guy was our speaker's enemy.

"He thought he'd 'list, perhaps,
Off-hand like—just as I—
Was out of work—had sold his traps—
No other reason why.

Although what, you ask? Although… the guy the speaker shot was probably a lot like the speaker himself.
Here the speaker imagines a life for the man he killed, and it wasn't much different from his own. He guesses that maybe the other guy enlisted (that's where that strange word 'list comes from) because he was out of work and needed a job (which is why he sold all his traps, or personal effects), probably never imagining that this one choice might lead to his death.
And all of a sudden—poof!—there goes the speaker's reason for killing this guy. Foe? Hardly. He's just another guy, trying to make a life for himself out there in the big bad world.
We've got a lot more dashes peppering these lines, which helps us remember that this is a spoken poem—that we're actually listening to a guy try (and fail) to work out his role in a violent war.
Here, the dashes make it sound like he's spitballing—just listing possible scenarios for this dead man's life.