Chametz spelled backwards is tzemach, a sprouting. This is logical since chametz is indicative of ego and haughtiness as the Gemara (Berachot 17a) indicates the yetzer hara is like the yeast in the dough. Tzemach though is representative of a small sprouting, rooted in the ground and springing forth.
When one thinks of tzemach, they think of the berachah in Shemoneh Esrei, “Et tzemach Dovid – the sprouting of Dovid.” We know tzemach is a reference to Moshiach, as the verse (Zecharia 6:12) says, “Thus said the God of Hosts: Behold, a man called the Branch shall branch out from the place where he is, and he shall build the Temple of God.” The branch (tzemach in Hebrew) is representative of the Messianic kingdom that will sprout forth to build the Temple.
Dovid, of course, saw himself “not even as high as a worm,” yet his supplications to grow are unparalleled. His ability to “branch out” was boundless, but he knew he was a mere sprout that was looking to grow, but never formed.
It is in the first chapter of Tehillim that we see Dovid pronounce, “He is like a tree planted beside streams of water, which yields its fruit in season, whose foliage never fades, and whatever it produces thrives.” Dovid’s ideal Jew is one who is continuously sprouting forth with vigor and vibrancy, never retiring to rote practice, but rooted in the ground.
Yet in Chapter 32 of Tehillim, spelling out lev, heart, in Hebrew, Dovid inserts the word seichel, mind. Because the heart must be ruled by the seichel, otherwise pure negative desires will take control. The Rambam enunciates this principle by noting that the mind follows the ratzon, desire.
Purim carries the theme of humility and negation which heightens over Passover, in holding the dough at bay, ultimately leading to total redemption.
Purim must precede Pesach. Firstly, Purim is a holiday of special powers, as the Shulchan Aruch uses the language that one must be in a state of “levasumei b’Puria – to be infatuated with Purim,” (not with wine), an idea presented by the Netivos Shalom. The power of Purim doesn’t differentiate between the cursed and blessed – God loves all Jews on Purim, setting us up for an embraced Passover.
In addition, Purim is about simcha, from the root word machah, to wipe away, because one must negate their essence first on Purim to come close to and exalt in the redemption of G-d on Passover.
We leave a state of negation with the knowledge that G-d runs every detail of nature and enter a sphere of the miraculous, knowing that the miraculous exists in every moment, and prepare for Dovid’s eminence to sprout and branch out around the globe.