Read "The Flight of Azrael" at The Eldritch Dark:
Clark Ashton Smith (CAS) used the poetic dialogue sparingly, but of the three such works I have read so far, they have all been excellent, and it seems like a formal structure that worked well for his particular creative inclinations.
As with many other pieces that flowed from his pen, here CAS' mood is rather gloomy, yet powerful and true:
It is the Earth,
A hoary planet, old in wrath and woe
As any hell. Red pestilence and war
Have now refunded to the usuring wind
The breath of all its peoples;
The cosmic vision that informs many of CAS' best verses provides the momentum in these lines, and some of the individual phrases have a dramatic focus that is breathtaking: "the thin wind / Will write man's epitaph in shifting sand".
In the worlds that CAS created, nothing is permanent, and none of humanity's creations will last. But that notion never seems morbid in the hands of this poet, since his recognition of the temporality of Beauty encourages his readers to make the effort to appreciate what we have right now.