The Purpose and Psychology Behind Mitzvah Performance
A key symbol of the recently celebrated chag of Sukkos is the arba minim - lulav, hadasim, aravos and esrog. It is well known that, when purchasing arba minim, observant Jews carefully examine the details of the samples offered for sale in the hope of purchasing as beautiful a specimen as possible - i.e., a "mehudar" for each of the minim. In other words, we don't just want "kosher" arba minim; we want the best.
The source of purchasing "mehudar" arba minim is the pasuk "zeh keli v'anveyhu - This is my G-d and I will beautify him." (Shemot, BeShalach 15:2). As the gemara in Shabbos (133b) explains, how does one beautify Hashem? The first opininon (Tanna Kamma) states that one beautifies Hashem through the embellished performance of mitzvot - i.e., making a beautiful sukkah, purchasing beautiful arba minim, a beautiful shofar, etc. That is, instead of being content with performing mitzvos within the letter of the law, we seek to optimize our performance through "hidur mitzvah" - that is, by acquiring the most beautiful specimen we can find (as an aside, in the sefer Iyun B'Lomdus by Rav Yitzchak Adler, pages 20-23, there appear some interesting analyses revolving around the chakira of whether "hidur mitzvah" is deemed part and parcel of the core mitzva, or constitutes its own independent mitzvah separate and apart from the core mitzvah being beautified; various nafka minot are discussed).
What's interesting is that a second opinion is brought down in the gemara concerning the meaning of the pasuk, "Zeh keli v'anveyhu." Abba Shaul states that "V'anveyhu" teaches us to emulate Hashem: "Ma hu rachum v'chanun, af ata rachum v'chanun - Just as Hashem is merciful and compassionate, so too, you [i.e., man] should be merciful and compassionate." (Shabbos 133b). This is how we "beautify" Hashem - by emulating His attributes.
So we have two opinions: the Tanna Kamma say that "zeh keli v'anveyhu" teaches hiddur mitzvah, and Abba Shaul opines that "zeh keli v'anveyhu" teaches emulation of Hashem's attributes of mercy and compassion (i.e., moral excellence).
I wonder - are these two tanaim arguing? Are their opinions mutually exclusive? IMHO, the answer is "No," and instead, based on the teachings of Rabbi Eliyahu Dessler, what we may actually have here is a progression; namely, that the stellar performance of mitzvos b'hiddur leads one to moral excellence (i.e., emulation of Hashem's attributes of mercy and compassion). If so, how does that work?