The promises made to Abraham and confirmed to his son were held by Isaac and Rebekah as the great object of their desires and hopes. With these promises Esau and Jacob were familiar. They were taught to regard the birthright as a matter of great importance, for it included not only an inheritance of worldly wealth but spiritual pre-eminence. He who received it was to be the priest of his family, and in the line of his posterity the Redeemer of the world would come. On the other hand, there were obligations resting upon the possessor of the birthright. He 178 who should inherit its blessings must devote his life to the service of God. Like Abraham, he must be obedient to the divine requirements. In marriage, in his family relations, in public life, he must consult the will of God.

De løfter, der var givet til Abraham og bekræftet over for hans søn, var det store mål for Isaks og Rebekkas længsler og håb. Både Esau og Jakob kendte disse løfter. De havde lært at betragte førstefødselsretten som noget meget vigtigt, for den indbefattede ikke alene en arv af verdslig rigdom, men også en åndelig forret. Den, der fik den, skulle være sin families præst, og verdens forløser skulle være af hans slægt. På den anden side hvilede der visse forpligtelser på den, der havde førstefødselsretten. Den, der skulle arve dens velsignelser, måtte vie sit liv til Guds tjeneste. Ligesom Abraham måtte han være lydig imod Guds krav. I sit ægteskab, i sit familieliv og i sin færden udadtil måtte han rådføre sig med Guds vilje.