HELP! PLEASE!!

Question

In martin luther king's speech, why does he choose the words "manacles of segregation and chains of discrimination" and what imagery is he envoking?

Answer 1

These are metaphors and he is associating segregation and discrimination with slavery, and stating that 100 years later, blacks were still struggling to achieve basic civil rights.  

Answer 2

Rob has it. His speech is on civil rights for blacks, and, since blacks suffered under slavery here in the US, he's using the imagery of chains and manacles to invoke ideas of slavery. MLK is equating segregation and discrimination to slavery; he's saying that the manacles of segregation and the chains of discrimination are just as strong, and just as wrong, as the literal manacles and chains of slavery. His point is that any black discriminated against and segregated is still as good as enslaved.