The speaker's mind is a big ball of guilt and confusion. He takes pride in his vast intelligence, but worries that he failed to use his "light" when he had it. You can imagine him saying, "How could I have known my vision was going to run out?!" His soul "bends" toward service of God like a flower bends toward the sun, but he is no longer fit for the kinds of intensive work that he might have done. He hopes that God does not blame him like the angry lord from the "Parable of the Talents" in the Bible.
The speaker mourns the loss of his "talents" in the political sphere and not in the practice of poetry.
Patience rescues the speaker from a vicious cycle that begins with guilty feelings toward himself and ends with blaming God for maintaining unreasonable expectations.