אִם יָבוֹא אֵלִיָּהוּ וְיֹאמַר-אֵין שׁוֹמְעִין לוֹ

ביטוי (אנגלית)

If Elijah comes and says — we do not listen to him

הגדרה (אנגלית)

Even if the prophet Elijah says so — one should not heed his words. By extension: there are clear and firm situations or fundamental principles that no one can challenge, no matter who they are.

("If Elijah comes and says that the rite is done with a shoe — we listen to him; if he says not with a sandal — we do not listen to him, for the many have practiced with a sandal and custom overrides the law" — Jerusalem Talmud, Yevamot 12:1)