Purim mitzvos reveal the hidden light of the day

בפסוק לעשות אותם ימי משתה ושמחה.

On the posuk: "to make them days of feasting and gladness" (Esther 9:22).

The Sefas Emes focuses on the word "to make (la'asos)" — that we are to actively "make" Purim into days of feasting and simchah.

שצריכין בנ"י בכח אלה המצות לגלות הארת הימים האלה.

That Bnei Yisrael must, through the power of these mitzvos, reveal the illumination of these days.

The mitzvos of Purim — the seudah, simchah, mishloach manos — are the tools through which we draw out and reveal the special light hidden within the day.

וכן שמעתי מפי מו"ז ז"ל רמז הלשון ליהודים היתה אורה כו' וששון.

And so I heard from my grandfather z"l a hint in the wording: "The Yidden had light... and gladness" (Esther 8:16).

He cites a teaching from his grandfather (the Chiddushei HaRim) on the precise language of the posuk describing the joy of the Yidden.

מה לשון נקיבה היתה.

Why the feminine form "haysah (there was)"?

The posuk uses a feminine verb form, "haysah," which calls for explanation.

לרמוז שבני שראל עתה משפיעין למדת ששון ושמחה שהם נעשין ע"י התעוררות בנ"י ודפח"ח.

To hint that Bnei Yisrael now give influence to the attribute of "sasson" and simchah — that these are brought about through the arousal of Bnei Yisrael; and these are beautiful words.

The feminine form signals receiving and being acted upon: on Purim, Bnei Yisrael themselves become the active "givers" who, through their hisorerus from below, generate the joy from above. The Sefas Emes praises the insight as "beautiful words."

ויתכן על דרך הלצה לרמוז זאת במאמרם ז"ל סעודת פורים שעשאה בלילה לא יצא ידי חובתו שנאמר לעשות אותם ימי משתה כו'.

And it is possible, by way of a play, to hint at this in the saying of Chazal: one who held the Purim seudah at night has not fulfilled his obligation, as it says "to make them days of feasting" (Megillah 7b).

He applies the idea to the halachah that the Purim feast must be held by day, reading the posuk's "days" as essential to its meaning.

פי' לא להתהלך בחשיכה לאכול ולשתות ניתנו ימי הפורים לנו.

The explanation: the days of Purim were not given to us to walk about in darkness, eating and drinking.

Purim is not meant for mere physical indulgence "in the dark," divorced from its deeper purpose.

רק לעשות אותם ימי משתה ושמחה לגלות הארת הימים והנסים שנעשו בימים ההם הנ"ל:

Rather, "to make them days of feasting and gladness" — to reveal the illumination of the days and the miracles that occurred in those days, as above.

The feasting must be held by day, in the light, because its whole purpose is to reveal the holy light of Purim and the nissim that Hashem wrought.

Summary: The mitzvos of Purim are the means by which Bnei Yisrael actively "make" and reveal the hidden illumination of the day. Citing the Chiddushei HaRim, the Sefas Emes explains the feminine "haysah" of "the Yidden had light" as hinting that on Purim the Jewish people themselves generate the joy from above through their arousal from below. This is why the seudah must be held by day and not "in the darkness" — its purpose is to reveal the light of the day and the miracles Hashem performed.