Refusing Amalek's spoil blots out his memory

מה שכפל ושילש במגילה ובבזה לא שלחו כו' ידם.

That which the Megillah repeats twice and three times — "but upon the spoil they did not lay their hand" (Esther 9:10, 15, 16).

The Sefas Emes notes that the Megillah stresses again and again that the Jews did not take the plunder of their enemies, even though they were permitted to.

נראה שהי' תיקון מה שהניחו שאול ובנ"י מעמלקים כמ"ש שם (למען) לזבוח לה'.

It appears that this was a rectification of what Shaul and Bnei Yisrael left over from Amalek, as it says there, "in order to sacrifice to Hashem" (Shmuel I 15:15).

This restraint repaired the earlier failure when Shaul and the people spared Amalek's livestock, claiming it was to bring as korbanos to Hashem. Now the Jews took nothing at all.

והשי"ת לא חפץ שיתקרב שום דבר מעמלק ימ"ש להקדושה.

And Hashem does not desire that anything of Amalek, may his name be erased, be brought near to holiness.

Unlike other things in the world, nothing belonging to Amalek may be drawn into the realm of kedushah — Amalek is to be utterly distanced.

לכן איתא שאין לקבל גרים מן עמלק.

Therefore it is taught that one does not accept converts from Amalek.

This is why halachah does not accept geirim (converts) from Amalek — there is no pathway to bring Amalek itself into kedushah.

ולכן אם כי כתב שללם לבוז.

And therefore, even though it wrote that "their spoil was for plunder."

Although the king's decree explicitly permitted the Jews to take the enemies' possessions as booty.

הי' נסיון לבנ"י שיזכרו שנאת עמלק.

It was a test for Bnei Yisrael, that they should remember the hatred of Amalek.

The permission to plunder was actually a nisayon (test): would the Jews recall that this enemy stems from Amalek, who must be wholly rejected?

ואף שהי' בכחם לבוז ולקרב להקדושה ג"כ ניצוצות מהם.

And even though it was within their power to take the plunder and to bring close to holiness even the holy sparks within them.

Even though the Jews could have seized the spoils and, in principle, elevated the nitzotzos (holy sparks) hidden within those possessions.

קיימו רצון התורה למחות זכר עמלק.

They fulfilled the will of the Torah to blot out the memory of Amalek.

They chose instead to carry out the ratzon Hashem of the Torah — to erase Amalek's memory entirely rather than extract any benefit from it.

[כי השי"ת שילם לעמלק כמדתו.

[For Hashem repaid Amalek measure for measure.

Hashem dealt with Amalek precisely according to Amalek's own character.

כי כל האומות אם כי חוטאים ג"כ.

For all the nations, although they too sin.

The other nations of the world are also sinful.

אבל רוצין להיות להם שייכות להקדושה.

Yet they desire to have some connection to holiness.

But the other nations still wish, on some level, to have a relationship with kedushah — and so their sparks can eventually be redeemed.

ועמלק נתיצב על הדרך להחטיא את בנ"י ולמרוד במקום.

But Amalek stationed himself on the road to cause Bnei Yisrael to sin and to rebel against the Omnipresent.

Amalek, by contrast, deliberately set himself in the way to drag the Jews into sin and into open rebellion against Hashem — he wants no part of holiness at all.

לכן לא יהי' לו זכר לעולם בתוך בני ישראל]:

Therefore he shall have no remembrance forever among Bnei Yisrael.]

Because Amalek's entire essence is opposition to Hashem, he can never be assimilated into kedushah, and his memory must be blotted out completely from among Bnei Yisrael.

Summary: The Megillah repeatedly stresses that the Jews took no plunder, rectifying Shaul's earlier sparing of Amalek's spoil. Unlike other nations, whose sparks can be drawn toward holiness, Amalek's very essence is rebellion against Hashem, so nothing of his may be brought near to kedushah — his memory must be utterly erased. Refusing the permitted plunder was the test, and the Jews passed it by fulfilling the Torah's will to blot out Amalek.