Reference for Megillah 35:13

וממאי דהאי זכירה קריאה היא דלמא עיון בעלמא לא סלקא דעתך (דכתיב) (דברים כה, יז) זכור יכול בלב כשהוא אומר לא תשכח הרי שכחת הלב אמור הא מה אני מקיים זכור בפה:

But how do we know that this zekhirah refers to reading [out loud]? Perhaps it means reading with the eyes? Do not think such a thing, since it has been taught: “Remember” [zakhor] (Deuteronomy 25:17). Do not think such a thing, since it has been taught: “Remember” [zakhor] (Deuteronomy 25:17). This might be only with the mind? When it says, “Do not forget,” forgetting in one’s heart is already stated. How then can I fulfill “remember”? With one’s mouth.

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