Blows as from the hatred of God; […] (2)
The speaker feels so strongly about the suffering he sees that he thinks that God must hate humanity. And if God hates humanity, then he'll probably want to punish it. And if God wants to punish someone, he probably knows how to do it—ever heard of a place called Hell? The speaker is comparing life to hell, because of the suffering he observes.
Perhaps they are […][…] the black heralds sent to us by Death. (7-8)
The black heralds here are usually linked to the four horsemen of the apocalypse, but there are other religious figures they could be connected to as well, like the angel of death. Either way, Death is a powerful spiritual force in this poem.
They are the deep falls of the Christs of the soul,of some adored faith blasphemed by Destiny. (9-10)
These lines pull directly from religious tradition, especially Christianity, to show the way that faith is always tested, and how what the soul most treasures is often the very thing that is taken away by life. Not a cheery thought, we know….