“He recalled (Zachar) His kindness and His faithfulness to the House of Israel; all ends of the earth have seen the salvation of our Lord.” (Psalm 98:3)
God is committed to Israel because of the merit of their forefathers, as stated in Michah 7:20: “”Give truth to Jacob, kindness to Abraham.” (Bereishit Rabbah 73:2) The Chidah elaborates (Chomat Anoch, quoting Tashbatz and Ari HaKodesh) that the letters of the name Yisrael allude to the initials of the patriarchs and Matriarchs: Yud – Yitzchak. Sin – Sarah. Reish – Rebecca & Rachel. Aleph – Abraham. Lamed – Leah.
Merit is timeless. It lives on in us and for us. God treats us as if the Patriarchs and Matriarchs were still alive and influencing us.
When we speak of Zichronot on Rosh Hashana, we are connecting to the timeless merit of our great ancestors. God connects us to them.