Dear Sir,--Your favor of the 21st inst., is this day received. It informs me that at a convention, (over which you had the honor to preside,) held at Dedham, on the 16th inst., I was unanimously nominated as a candidate for Representative to the thirty-second Congress of the United States. For the kind terms in which your communication is expressed, be pleased to accept my thanks. This nomination places me in no new relation to the friends of freedom and humanity, wherever they may be found. I believe my name was first suggested to the voters of this district, (now nearly three years ago,) on the ground of my supposed devotion to the rights of men. The resolutions passed at all the conventions by which I have been nominated, and especially those passed so repeatedly and unanimously by our state legislature, have been in the nature of instructions; or, at least, of urgent advice and solicitation, in regard to my course on the great questions which have since agitated the country. My own convictions of duty so fully and entirely corresponding with the injunctions thus laid upon me, it has been easy for me to act in full conformity to the wishes of the great majority of my constituents and of the state, as those wishes have been repeatedly expressed. This renders any detailed exposition of expectations on your part, or of assurances on mine, unnecessary. I know that the leading and most valued article in your creed is the sacredness and security of human freedom. You know that I embrace this same article of faith with my whole heart. Other matters may be very important, but still are subordinate. Peculiar forms of organization are comparatively non-essentials. They are but means to ends; and, in regard to them, a large allowance is to be made for honest differences of opinion. But the natural right of every human being to the liberty which God has given him, until forfeited by crime of his own; the duty of our government to save every part of this earth over which it has jurisdiction from the direst of all earthly curses and the greatest of all social crimes,--the curse and the crime of slavery;--these are among the first of the dread accountabilities that attach to rational and immortal creatures.