In his commentary on this verse, the Vilna Gaon writes that the expressions used in this verse refer to the four components of man – the nefesh (animus, ability to move), the ruach (life force), the neshama (spiritual soul), and the guf (physical body). He writes that the nefesh and guf are really one, as according to the Zohar which writes that “the nefesh is a partner to the guf.” Haman wanted to destroy every part of the Jew; he therefore used three expressions to denote his real intent. However, the neshama is fed by performance of mitzvos, the ruach is fed by pleasure, and the guf is fed by food. The Vilna Gaon writes that this is the reason for the three mitzvos of Purim; publicly reading the Megillah (see Esther 8:26) feeds the neshama, having joy (see Esther 8:17) feeds the ruach, and feasting (ibid.) literally feeds the guf. There is also an extra mitzvah of giving gifts (ibid. 19). Perhaps Haman’s desire to plunder the Jews’ wealth is the reason we use our resources for this last mitzvah.
R’ Dovid Chadida writes similarly that by using the word “l’hashmid” (“to destroy”), Haman intended to kill the Jews spiritually, by using the word “l’harog” (“to kill”), Haman intended to kill the Jews’ physically, and by using the word “l’aveid” (“ to annihilate”), Haman intended to kill the Jews’ financially. In the verses of Shema (Devarim 6:5), these are the very three things with which Jews are expected to dedicate themselves to love H-Shem.