
“Ambition breaks the ties of blood, and forgets the obligations of gratitude.”
As quoted in History of the Anti-Corn Law League (1853), by Archibald Prentice, p. 54; around 1876 this began to began to be cited to W. Scott, and then around 1880 sometimes to Walter Scott, but without citations of source, including a variant: "Selfish ambition breaks the ties of blood, and forgets the obligations of gratitude" in a publication of 1907.