The mitzvah of bikurim requires an individual to designate the first fruit of his labor (i.e. hafrasha) and to subsequently bring them to the beis hamikdosh (i.e. hava'ah). The Rambam maintains (Sefer Hamitzvos, mitzvas asseh 125) that these two elements, hafrasha and hava'ah, comprise a single mitzvah. Rabbeinu Sadyah Gaon, however, disagrees and treats hafrasha and hava'ah as two separate mitzvos (mitvas aseeh 81 and 84).
At first glance, this dispute seems to parallel the views of the Rambam and Ramban regarding the obligation of terumah. Whereas the Ramabm sees hafrasha and nesina, designating and giving terumah to the kohein as a single mitzvah (mitzvas asseh 126), the Ramban counts hafrasha and nesina as two separate mitzvos (shoresh 12).
The view of the Ramban, however, is not at all identical to the position of Rav Sadyah Gaon. The Ramban explains that hafrasha is independent of nesina, for through hafrasha one removes the prohibition of tevel. This reasoning which most certainly applies to terumah and challah, does not apply to bikurim, which is not linked to the prohibition of tevel.
Although the Rambam combines the elements of hafrasha and hava'ah, he nonetheless treats mikra bikurim, the profound declaration of gratitude to Hashem, as an independent mitzvah (mitzvas asseh 132).
The primacy and importance of bikurim is evident in a striking medrash. Rashi, commenting on the opening pasuk of Braishis, explains "bishvil haTorah shenikrais raishis darko" - the world was created for the Torah which is called the beginning of His way - "ubishvil Yisroel shenikra raishis tevuaso" - and for Yisroel which is called the first of His crop. The medrash adds "v'ein raishis ela bikurim, d'ksiv 'raishis bkurei admaschem'" - "the beginning" refers to bikurim, the choicest first fruit of your land. In what sense, however, is bikurim a mitzvah in whose merit the world was created?
Rav Asher Weiss explains that this perplexing medrash can be understood based on the stunning comments of the Ramban (end of Parshas Bo), "v'ein keil elyon chafets b'tachtonim milvad she'yeida ha'adam v'yodeh l'elokav she'bra'av" - Hashem, the Most High, has no demand on the lower creations except that man should know and be thankful to Hashem for having created him. Hava'a and mikra bikurim reflect these two imperatives - she'yeida v'yodeh. By offering his first fruits, hava'a, man demonstrates that Hakadosh Baruch Hu is indeed the supreme creator, borai hakol. Through mikra bikurim, one declares profound gratitude, recognizing Hakadosh Baruch Hu as the guide of our history and destiny. The mitzvah of bikurim reflects our challenge and mandate she'yeidah v'yodeh. In this merit the world was created.