But ah, but O thou terrible, why wouldst thou rude on me Thy wring-world right foot rock? lay a lionlimb against me? scan With darksome devouring eyes my bruisèd bones? and fan, O in turns of tempest, me heaped there; me frantic to avoid thee and flee? (5-8)
More than one critic has compared this poem to the biblical Book of Job, in which Job is basically tortured by God via a series of misfortunes. At the end, though, Job comes to realize the importance of God in his life, just as the speaker does in this poem. They both start, though, with a simple (and probably familiar) question: "Why me?" In these lines, the speaker uses personification to show how awful things are for him. It's like he's being crushed by a monstrous lion, then subjected to violent storms. What sort of God would do this to him?
Nay in all that toil, that coil, since (seems) I kissed the rod, Hand rather, my heart lo! lapped strength, stole joy, would laugh, chéer. (10-11)
After detailing the depths of his depression, the speaker turns in the second stanza, realizing that he's actually grateful for having been treated by God in this way. The bad times that he's endured have allowed his heart to grow stronger and more pure. Thanks, God.
Cheer whom though? the hero whose heaven-handling flung me, fóot tród Me? or me that fought him? O which one? is it each one? (12-13)
These lines pose an interesting question: should the speaker be cheering for himself for having overcome depression, or should he be giving props to God for sending the depression to him in the first place? Maybe it's a little bit of both? This kind of question is really at the heart of a lot of religion: where does God's influence end and individual responsibility begin?
[…] That night, that year Of now done darkness I wretch lay wrestling with (my God!) my God. (13-14)
The speaker's big reveal—which is news to him as well—comes in these final lines of the poem. All this time that he's been struggling with depression, he's actually been undergoing a kind of divine test, sent to him by God to strengthen his character.