Since the Israelites had rejected the Lord, He would no longer protect them. Moses had learned centuries before that man is nothing without the help of God, 'for this cause I know that man is nothing, which thing I never had supposed' (Moses 1:10). As individuals or as a nation, we cannot afford to live "without the Lord." If we try, we will likely suffer the same fate as the Israelites.
Brigham Young
"Our religion incorporates every act and word of man. No man should go to merchandising unless he does it in God; no man should go to farming or any other business unless he does it in the Lord. No man of council should sit to judge the people but what should judge in the Lord that he may righteously and impartially discern between right and wrong, truth and error, light and darkness, justice and injustice. Should any legislature sit without the Lord? If it [does], sooner or later it will fall to pieces. No nation ever did live that counseled and transacted its national affairs without the Lord, but what sooner or later went to pieces and came to naught. The same is true of all the nations that now live or ever will live." (Discourses of Brigham Young, ed. by John A. Widstoe, p. 9)