He is addressing the then mayor of Pittsburgh, PA:
“Honorable Mayor, whatever ideas of liberty I may have, have been received from reading the lives of your revolutionary fathers. I have therein learned that a man has a right to defend his castle with his life, even unto the taking of life. Sir, my house is my castle; in that castle are none but my wife and my children, as free as the angels of heavens, and whose liberty is as sacred, as the pillars of God.
If any man approaches that house in search of a slave, I care not who he may be, whether constable, or sheriff, magistrate or even judge of theSupreme Court, nay, let it be he who sanctioned this act to become a law. (President Millard Fillmore) surrounded by his cabinet as his bodyguard, with the Declaration of Independence waving above his head as his banner, and the constitution of his country upon his breast as his shield, if he crosses the threshold of my door, and I do not lay him a lifeless corpse at my feet, I hope the grave may refuse my body a resting place, and righteous Heaven my spirit a home. O, no! He cannot enter that house and we both live.” source: http://pan-afrikan-education.tumblr.com/post/66659991320/martin-delany-this-is-his-personal-response-to