Line 33

Now a promise made is a debt unpaid, and the trail has its own stern code.

• Our speaker has a lot to say about the importance of promises. It turns out to be a big theme here. He feels like he owes his dead friend a debt.
• Seems like it has something to do with the "stern code" of the trail. Basically, this means that there’s a system of honor for guys who travel in the wild like this. Think of it as being like the bond between soldiers. You stick together, you help your friends, but most of all, you keep your word.

Line 34

In the days to come, though my lips were dumb, in my heart how I cursed that load.

• Our speaker knows what he has to do, but it's not easy. He won’t let himself say it aloud, but deep down in side, he hates having to drag his friend’s dead body around. Which we think it pretty understandable. We mean, we’ve heard of helping out your buddies, but this takes it pretty far.

Line 35-36

In the long, long night, by the lone firelight, while the huskies, round in a ring,
Howled out their woes to the homeless snows— O God! how I loathed the thing.

• The speaker paints a pretty miserable picture of the rest of this trip. These lines are especially lonely and grim. He gives us an image of the long, cold nights, surrounded by the sad howls of the sled dogs.
• We actually like that line a lot: "Howled out their woes to the homeless snows." Can’t you just feel a shiver of sadness and isolation in those lines? It really helps us to see how miserable it would be to carry around Sam’s body, which by now the speaker just calls "the thing."