He said to him, “You swore, and I swore that I would not come down from the altar until I say all that I must.” He said to Him, “Say, is this not what You said to me, ‘Count the stars; if you can count them, so will be your descendants’?” He said to him, “Yes.” He said to Him, “From whom?” He said to him, “From Isaac.” He said to Him, “Just as when I had in my heart what to answer You and tell You, yesterday You said to me, ‘through Isaac your descendants shall be named,’ and now You tell me, ‘Offer him there as a burnt offering,’ and I restrained myself and did not answer You. Likewise, when Isaac’s sons sin and put themselves in trouble, You will remember the tying of Isaac and will regard it as though his ashes are piled up on the altar, and You will forgive them and redeem them from their trouble.”

The Creator said to him, “You said yours, and I will say Mine.” Isaac’s sons are destined to sin before Me and I will judge them in the beginning of the year. If they want Me to seek their merit and remember for them the tying of Isaac, let them blow before Me with a Shofar of one.

This means that we can extend ancestral merit only through work, which is the work in Mitzvot [commandments]. The meaning of Shofar [a festive horn] is “Shapru [improve] your works,” and the covenant will not be broken, for through the act, “A covenant of fathers You shall remember for the sons” will be extended to them.