Parashas Shemos
וַיֹּ֗אמֶר אָנֹכִי֙ אֱלֹהֵ֣י אָבִ֔יךָ אֱלֹהֵ֧י אַבְרָהָ֛ם אֱלֹהֵ֥י יִצְחָ֖ק וֵאלֹהֵ֣י יַעֲקֹ֑ב וַיַּסְתֵּ֤ר מֹשֶׁה֙ פָּנָ֔יו כִּ֣י יָרֵ֔א מֵהַבִּ֖יט אֶל־הָאֱלֹהִֽים׃
and continued, “I am the God of your fatherdyour father Including his household.—the God of Abraham, the God of Isaac, and the God of Jacob.” And Moses hid his face, for he was afraid to look at God.eGod Or “a divine being.”
Torah Temimah points to Sifra / TT (verified).
אלהי אברהם וגו׳ — יכול כל הקודם בדבר חשוב מחבירו? ת״ל וזכרתי את בריתי יעקוב\ldots מגיד ששלשתן שקולים.
English: “God of Avraham\ldots” — Might one think that whoever is mentioned first is more important than his fellow? Therefore Scripture says “And I will remember My covenant with Yaakov\ldots,” teaching that all three are equal.
Custom
Chazal teach that the three Patriarchs are of equal standing before God.