Why does it say "these days
Torah Temimah citing Megilah 20a #1: We read the Megilah only after sunrise - during the day, and not at night 1 .
Torah Temimah citing Megilah 20a #2: The entire day is Kosher to read the Megilah.
Tosfos (4a DH Chayav): The primary reading is during the day.
What do we learn from "Nizkarim"?
Torah Temimah citing Megilah 18a: If one read the Megilah by heart, he was not Yotzei. We learn from a Gezeirah Shavah Zechirah-Zechirah from "Kesov Zos Zikaron ba'Sefer" (Shemos 17:14), which must be in a Sefer.
What do we learn from "Nizkarim v'Na'asim"?
Torah Temimah citing Megilah 18a: If one read the Megilah out of order, he was not Yotzei. "Nizkarim v'Na'asim" equates the remembrance (Keri'ah) with the doing, which cannot be out of order. Also reading may not be out of order.
Torah Temimah (19, citing Megilah 2b): This equates remembering (Keri'as ha'Megilah) to doing. Just like Mishteh and Simchah are on the 14th for open cities and 15th for walled cities, also Keri'as ha'Megilah.
Rashi: They are "Nizkarim" via Keri'as ha'Megilah, and "Na'asim" via Mishteh, Simchah and Yom Tov 1 , via giving [Mishlo'ach] Manos and Matanos [la'Evyonim].
Why does it say "Mishpachah u'Mishpachah"?
Vilna Gaon and Torah Temimah, from Megilah 3a: This teaches that families of Kohanim and Leviyim abandon Avodah and go to hear the Megilah.
Rashi: Families gather together and eat and drink together.
What do we learn from "Medinah u'Mdinah"?
Vilna Gaon and Torah Temimah, from Megilah 2b: This distinguishes between walled cities from the time of Yehoshua bin Nun and those surrounded afterwards [from the time of Achashverosh].
What do we learn from "v'Ir va'Ir"?
Torah Temimah citing Megilah 2b #1: This distinguishes between Shushan and all other cities.
Megilah 2b #2: Any place close to a walled city or that can see a walled city has the law of a walled city.
Vilna Gaon: Ir is a village without 10 Batlanim 1 (people without a job; they are also in the Beis ha'Keneses).
The Heter to read the Megilah before the 14th (refer to 9:22:1:1, 9:22:1:1 2
) is only for such places. Presumably, the Vilna Gaon expounds to distinguish between cities with 10 Batlanim and those without, for (a) if not, the verse implies that cities with 10 are exempt, and (b) We should learn two matters from "v'Ir va'Ir", just like from "Mishpachah u'Mishpachah" and "Medinah u'Mdinah." (PF)
Why does it say "v'Zichram Lo Yasuf mi'Zar'am"?
Rashi: Zichram (Keri'as ha'Megilah) will not cease from them. The Targum of "Ad Tom" (Devarim 2:14) is Ad d'Saf.
Vilna Gaon: Zichram, i.e. Keri'as ha'Megilah, will not cease from Zar'am, i.e. minors; even they are obligated in it. This is unlike "Yemei Purim", i.e. Mishteh and Simchah, which will not depart from ha'Yehudim (adults); minors are exempt from them.
