The birthright held great importance [in Jacob’s day]. “Under the Patriarchal Order certain special blessings, rights, powers, and privileges – collectively called the birthright – passed from the father to his firstborn son. (See Gen. 43:33.) In later ages special blessings and prerogatives have been poured out upon all worthy descendants of some who gained special blessings and birthrights.” (Bruce R. McConkie, Mormon Doctrine, 2nd ed. p. 87.)
The birthright comprised a number of specific blessings, among them: (1) the right to bear the priesthood, and (2) the right to prosper.
. . . “I swear unto you, that inasmuch as ye shall keep the commandments of God ye shall prosper in the land. . . . I do know that whosoever shall put their trust in God shall be supported in their trials, and their troubles, and their afflictions, and shall be lifted up [or, exalted] at the last day.” (Alma 36:1,3) — The Church News, June 25, 1994, p. 11