Plato gave this advice in The Republic (using different words).
William Makepeace Thackeray is believed to have coined the phrase in the 1850s (as reported in Laurence Hutton’s memoir).
The quote was eventually, and probably wrongly, attributed to Abraham Lincoln for the first time in 1946, 81 years after his death (Lincoln was born on this day in 1809)
The theme was delivered beautifully by Martin Luther King Jr. in his 1967 speech “What is Your Life’s Blueprint” (in the excerpt better known as “The Street Sweeper”).
On the surface, this quote seems to exhort us to simply be good at our craft, to hone the skills required of our job. Of course, it is much more than that. Those words urge us to forge our character and to seek justice.
Some would say we should seek justice for all mankind. I find it a tall order. I think it would suffice if all of us were just farmers and street sweepers, just children and parents, just employees and bosses.
Let us be just men and women.
The Ethical Leader 