“The indoctrinated's different drummer is a metronome.”

Day of Affirmation Address (1966)
Context: All do not develop in the same manner, or at the same pace. Nations, like men, often march to the beat of different drummers, and the precise solutions of the United States can neither be dictated nor transplanted to others. What is important is that all nations must march toward increasing freedom; toward justice for all; toward a society strong and flexible enough to meet the demands of all its own people, and a world of immense and dizzying change.

Walden

Lloyd v. Wooddall (1748), 1 Black. 30.

Often apocryphally and jokingly attributed to Lennon in an interview where he was asked whether fellow Beatle Ringo Starr was the best drummer in the world. https://www.snopes.com/fact-check/john-lennon-ringo-best-drummer/
Misattributed

Academy of Achievement interview (1991)
Context: I have come to associate a kind of success that we are referring to, to individuals who have a combination of attributes that are often associated with creativity. In a way they are mutants, they are different from others. And they follow their own drummer. We know what that means. And are we all like that? We are not like that. If you are, then it would be well to recognize that there were others before you. And, people like that are not very happy or content, until they are allowed to express, or they can express what's in them to express. It's that driving force that I think is like the process of evolution working on us, and in us, and with us, and through us. That's how we continue on, and will improve our lot in life, solve the problems that arise. Partly out of necessity, partly out of this drive to improve.

Bullet in a Bible (2005) (on the tour bus).

Source: The Total Money Makeover: A Proven Plan for Financial Fitness

Source: City of Heavenly Fire

Song lyrics, The Freewheelin' Bob Dylan (1963), A Hard Rain's a-Gonna Fall