I have never knew what it was to sacrifice my own judgment to gratify any party and I have no doubt of the time being close at hand when I will be rewarded for letting my tongue speak what my heart thinks. I have suffered myself to be politically sacrificed to save my country from ruin and disgrace and if I am never again elected I will have the gratification to know that I have done my duty.
Source, in full
Comments on his final election defeat (11 August 1835) Ch. 2; in Dr. Swan's Prescriptions for Job-Itis (2003) by Dennis Swanberg and Criswell Freeman, p. 45, part of this seems to have become paraphrased as "Let your tongue speak what your heart thinks." No earlier publication of this version has been located.