"The Wild Iris" begins with some bold claims, told in a mysterious first-person voice: a voice that claims to have died, and lived to tell the tale.
Not only has this speaker died and returned to life, they really, really want the reader to hear their story and to believe it. Listen to the urgency of the caesura and the enjambment in lines 3-4:
Hear me out: || that which you call death
I remember.
That mid-line colon feels insistent, asking the reader to stop and really listen. Then, the enjambment sets off the strange idea that this speaker can "remember" their own death, giving this powerful declaration a whole line to itself.
Already, then, the reader has the sense that this speaker is someone who's been through an astonishing experience. And going through that experience has made them want to share it. This speaker wants to be heard, to communicate a powerful message: death isn't the end.
Take a look at the metaphor in the poem's very first lines:
At the end of my suffering
there was a door.
If there's a "door" at the end of suffering, then suffering itself isn't an infinite void, or a devouring monster. Instead, it's something more like a dark hallway: a difficult passage to navigate, but still a passage, a thing that takes people from one place to another.
And the way these two first stanzas mirror each other—each is only two lines long, and each is a single enjambed sentence—suggests that the speaker's "suffering" and their "death" are one and the same. Death isn't pure oblivion, but a painful passage—a trial, not an ending.
In other words: to this speaker, pain and death aren't terrible and irreversible fates. They're part of an ongoing journey.