For a law; either that it might be as firm and irrevocable, as a law; or that it might have the use and force of a law towards God, because God did hereby put himself under an obligation of making it good in regard of his own truth and righteousness.
Related Commentaries of Psalms 105:10
Psalms 105:10
10 And confirmed the same unto Jacob for a law, and to Israel for an everlasting covenant: