I would have the constitution torn in shreds and scattered to the four winds of heaven. let us destroy the constitution and build on its ruins the temple of liberty. i have brothers in slavery. i have seen chains placed on their limbs and beheld them captive meaning

This passage is explaining that although the Constitution seemingly boasts equality, in reality there still exists unfair treatment of other humans in the form of slavery. Therefore the speaker is claiming that the Constitution should be rewritten to protect against slavery and other forms of abuse and discrimination.