Follow, poet, follow rightTo the bottom of the night,With your unconstraining voiceStill persuade us to rejoice; (54-57)
If Auden admires Yeats for anything, it's his tenacity. Yeats was dogged in pursuing his own visions, no matter how obscure they might have seemed to other people. In these lines, Auden seems to suggest that perhaps it wasn't Yeats's language that was obscure; maybe it was the darkness of time in which he was living.
In the prison of his daysTeach the free man how to praise. (64-65)
The last lines of this poem are a whole bundle of contradictions. Man is both imprisoned and free. He's limited by his "days" (everyone dies sometime), but he's able to learn and grow and, well, praise. If anything, these lines demonstrate just how difficult the task Yeats undertook actually was. "Praise" sure isn't the first thing that would be on our minds. And, as far as this poem is concerned, it's that struggle against the impossible that best characterizes Yeats's work.