ואספת דגנך ותירשך ויצהרך ... (יא-יד)
In the second parsha of Krias Shema, three types of produce of Eretz Yisroel are mentioned; "דגנך ותירושך ויצהרך" - grain, wine, and oil. “Dagan” refers to the five grains from which one must take terumos and maasros: wheat, barley, rye, spelt and oats. The Gemara (Berachos 40a) explains that a child begins to develop da’as, mental ability, only after he or she begins to eat grain: “A baby only knows how to call Father and Mother after he has eaten grain.” The eating of grain stimulates mental growth! The grain that is grown in Eretz Yisroel, however, is special since it is grown in an atmosphere of kedusha. It therefore promotes a higher level of intelligence than ordinary grain would - that of Da’as Elokim.
“Tirosh” - the wine that is squeezed from grapes of Eretz Yisroel (from which nesachim are poured with the korbanos) has a unique quality. This wine creates much simcha. In Tehillim (10:15) it says, "ויין ישמח לבב אנוש" - “Wine gladdens a man’s heart.” Although a person can get giddy from any wine, it is the wine of Eretz Yisroel that creates a feeling of spiritual joy and happiness. Obviously, this simcha is very different than ordinary frivolity.
“Yitzhar” - oil from olives that are grown in Eretz Yisroel, used for korbanos as well as to light the menorah in the Bais HaMikdash, has a the ability to enlighten one’s mind to a deeper understanding of Torah, to achieve the “Ohr HaTorah” - the light of Torah. The highest level of this unique “Ohr” would be Ruach HaKodesh.
These 3 forms of produce and their spiritual effect on people are alluded to in the words, "תדשא הארץ דשא" - “Let the earth bring forth vegetation.” The letters of "דשא" - stand for "דעת"(knowledge), "שמחה" (joy) and "אור" (light). Thus, we say in “Al Hamichya,” that Hashem gave us the Land of Israel, "לאכול מפריה ולשבוע מטובה" - in order to eat from its fruit and be satiated from its goodness! In other words, the very purpose that Hashem gave us the Land was in order for us to eat from its produce! May the mitzvah of eating the fruit of Eretz Yisroel help us expand our daas, simcha, and ohr, bringing us closer to Hashem.