The  belief behind Jeffersons Agrarian Ideal was that:-

"Those who labor in the earth are the chosen people of God, if he ever had a chosen people, whose breasts he has made his particular deposit for substantial and genuine virtue. It is the focus in which he keeps alive that sacred fire, which otherwise might escape from the face of the earth. Corruption of morals in the mass cultivator is a phenomenon of which no age nor nation has furnished an example"

Jefferson's version of "chosen people", then is a class, not a nation. If Americans are chosen in any way. it is because they belong largely to this group; it is favoured by providence because of its mores, not because it has been designated to play a historical role...the "plain honest manners," the lack of aristocratic distinction, the honest toil of the enhabitants of the new Eden"

Ernest Lee Tuveson Redeemer Nation: The Idea of American's Millenial Role, University of Chicago Press, Chicago, 1968, 109

Jefferson wanted to educate and assimilate the Indian into the agrarian lifestyle, "the mass cultivator" , that was the basis for the 'moral' virtues of the American people. Teaching and encouraging them to use the land and become civilised enabling them to live with the American people as Americans and purchasing any land that the American Nation might require incorporating the Indian into white society and their mission