Torah Temimah citing Megilah 19a: The Megilah must be written in a Sefer, in ink. We learn a Gezerah Shavah "Kesivah-Kesivah" from "va'Ani Kosev Al ha'Sefer bi'Dyo" (Yirmeyah 36:18).

Vilna Gaon: Esther and Mordechai wrote the Megilah with Ru'ach ha'Kodesh ¹ , and sent it in an Igeres.

Torah Temimah citing Megilah 19a #1: One must read the entire Megilah, i.e. the Tokef (might) of Achashverosh.

Torah Temimah citing Megilah 19a #2: One must read from "Ish Yehudi", i.e. the Tokef of Mordechai.

Torah Temimah citing Megilah 19a #3: One must read from "after these matters", i.e. the Tokef of Haman.

Torah Temimah citing Megilah 19a #1: One must read from "on that night", i.e. the Tokef of the miracle.

Rashi: It is the Tokef of the miracle, Achashverosh, Haman, Mordechai and Esther.

Malbim: Esther wanted that the Megilah will be part of Kesuvim; initially, they refused (Megilah 7a), for one may not add to Kisvei ha'Kodesh ¹ . There was also a complaint against fixing Yemei Purim permanently, due to Bal Tosif. She joined with Mordechai and wrote with the Tokef (power) of kingship in her hand ² to be Mekayem the Megilah (make it part of Kesuvim).

Vilna Gaon: They will read and fulfill what is in it.

Malbim: The Megilah should become part of Kesuvim (refer to 9:29:2:6).

Torah Temimah citing Megilah 19a: The Megilah is called "Sefer ¹ " and it is called "Igeres" (a letter). "Sefer" disqualifies a Megilah sewn with flax (such a Sefer Torah is Pasul). "Igeres" teaches that three stitches of a sinew suffice. The stitches must be evenly spaced.

Torah Temimah citing Megilah 7a: At first, Purim was enacted in Shushan; later, it was enacted everywhere.

Refer to 9:27:7:2 and the note there.

Rashi: In the second year, they sent Seforim that people should do Purim.

Malbim: It is our text of the Megilah.