Get out the microscope, because we’re going through this poem line-by-line.
They are few; but they are…. They open dark trenches
in the fiercest face and in the strongest back.
- These lines are still about the "blows." Here the speaker compares them to a plow opening up trenches, or maybe a whip that leaves marks on people's bodies. This might make you think of slavery, or, for a more religious angle, self-flagellation (where folks whip themselves to emulate Jesus' suffering). Heck, it might remind you even of Jesus Christ himself, being beaten on his way to the cross. This religious symbolism is going to get stronger really soon, in case you think it sounds kind of out-of-left-field.
- Also notice the alliteration in line 6: "fiercest face." When you repeat an /f/ sound, you have to force (there it is again!) air out through your teeth and lips, like a puff of wind, or a gob of spit. Either way it's a forceful expulsion, kind of the kind you might associate with God raining his hatred down on humanity.
- Finally, these lines contain synecdoche too, using a part to represent a whole (like "all hands on deck"). In this case, the speaker mentions dark trenches in a face and a back, but that's not what's literally meant. The face and back are just parts that are used to represent the whole person. Those dark trenches, then, become more profound than just physical scars. They weigh on the whole person. Bummer!
Perhaps they are the colts of barbaric Attilas;
or the black heralds sent to us by Death.
- Here the speaker starts to ponder what the blows might be, instead of just describing them. They might be the colts of Atilla the Hun, which brings to mind a super-scary warrior coming to wipe you out. Eek.
- If that image isn't freaky enough, how about some black heralds, or messengers, sent by Death? Sound fun? So all of our suffering throughout life is just little reminders that "Hey, you're going to die someday!"
- These lines use metaphor to compare suffering to the colts or the heralds, and these active, moving images give us the feeling that suffering is not a passive thing—it's coming for us.