No lands acquired under the provisions of this Act shall, in any event, become liable to the satisfaction of any debt contracted prior to the issuing of the final patent in fee therefor.
25 U.S. Code § 354 - Lands not liable for debts prior to final patent
(Feb. 8, 1887, ch. 119, as added June 21, 1906, ch. 3504, 34 Stat. 327.)