Who said "our manifest destiny to overspread the continent allotted by providence for the free development of our yearly multiplying millions"?

John O'Sullivan, journalist and editor, coined the term "manifest destiny". By this he was referring to the inevitably of the spread of the United States over the continent, from coast to coast. This would involve subjugation of the native "savages" and the use of the land for the development of the American population and developing culture.