Manifest Destiny was a belief that America was destined by God, Himself, to expand her borders from the Atlantic coast to the Pacific coast.
"In an essay on "Annexation" published in the United States Magazine and Democratic Review in the summer of 1845, John L. O'Sullivan (1813–1895) proclaimed that it was the "manifest destiny of the United States to overspread the continent allotted by Providence for the free development of our yearly multiplying millions" (p. 5)."
There was a general belief, although not an official government position, that the borders of the United States should be expanded as far west as the Pacific Ocean.
"God has predestinated, mankind expects, great things from our race. . . . The rest of the nations must soon be in our rear. We are the pioneers of the world; the advance-guard, sent on through the wilderness of untried things, to break a new path in the New World that is ours."
It was as if America was on a mission, destined by God to provide their brand of living to as many people as possible. This ideology led to the Homestead Act of 1863 encouraged westward expansion by offering land 160 acres which you could keep after 5 years if you built a house on it, dug a well, farmed the land.
"And we Americans are the peculiar, chosen people—the Israel of our time; we bear the ark of the liberties of the world. Seventy years ago we escaped from thrall; and, besides our first birth-right—embracing one continent of earth—God has given to us, for a future inheritance, the broad domains of the political pagans, that shall yet come and lie down under the shade of our ark"
The call to move west was taken as a sacred oath, a duty that was directed by God to bring the faith and stability of the American nation to the wild, untamed wilderness of the West.