Musar zu Jirmejahu 31:11

The answer is found in the fact that it was Jacob who redeemed Abraham as we have learned from Jeremiah 31,11. Abraham was saved from Nimrod's furnace only in order for Jacob to be born in the future. This does not mean that Jacob's merits were greater than those of Abraham. On the contrary; Abraham, the founder of Judaism, possessed comprehensive merits. He had such great merit that he should not have been denied the ultimate merit of being a martyr for his faith. Had G–d allowed such martyrdom, however, Jacob would never have seen the light of this world. The fact that Jacob's מטתו שלימה, that he raised all his children to remain loyal to his teachings, represented the mystical dimension of completing the בנין in the Celestial Regions, as we have described this elsewhere.