“blank verse” refers to

poetry with fourteen lines and a pattern of rhyme
poetry without rhyme or meter
unrhymed poetry written in iambic pentameter
poetry in which every other line rhymes

“thy baited hooks shall tangle me no more.”

“hath taught me to set in trifles no store,”

“me lusteth no longer rotten boughs to climb.”

the answer is slaves

douglas was a slave who turned into a statesman and he refused to celebrate the 4th of july until all slaves were emancipated or set free.