The Mitzva to Cultivate the Holy Fruit of “Eretz Ha-Tzvi”
The sanctity of the fruits of Eretz Yisrael, which grow from the land, finds expression in another mitzva as well: cultivating the earth of Eretz Yisrael and growing fruit in it, as Chatam Sofer explains:
In my humble opinion, R. Yishmael only invoked the verse of
“you shall gather your grain” with regard to Eretz Yisrael when the majority of Israel is on their land, when working the land is itself a mitzva of settling Eretz Yisrael and bringing forth its holy fruits. Regarding this, the Torah commanded “and you shall gather your grain.” Boaz winnowed on the threshing floor at night because it was a mitzva. As it is absurd to say "I will not put on tefillin because I am busy studying Torah", so too one should not say "I will not gather my grain because I am busy studying Torah." It is possible that even other trades that contribute to civilization all have the status of a mitzva. However, when due to our many sins we are scattered amongst the gentile nations, and “one who contributes to world civilization further destroys worship of God”, R. Yishmael would concur with R. Shimon b. Yochai! (but in Eretz Yisrael all agree with R. Yishmael that there is a mitva to settle the land which is not deferred by Torah study)… (Chidushei Chatam Sofer, Sukkah 36a)
Chatam Sofer’s words are very powerful. He gives this mitzva of bringing forth the holy fruits of Eretz Yisrael the highest priority; it is not even deferred by Torah study! This mitzva puts agriculture in Eretz Yisrael on a different level than any other land:
Agriculture – the primary element of any civilized land – for
all the nations is nothing but a normal economic factor. But for the nation whose life-content is the holiest of the holy, and whose land, language, and values are holy in their entirety, agriculture is also imbued with holiness.
According to R. Kook, cultivating the fruit of Eretz Yisrael is a sacred value, not merely agriculture as an element of the economy. This insight also underlies the historical dispute between the Pharisees and the Boethusians regarding whether harvesting for the Omer offering supersedes Shabbat:
This sanctity underlying agriculture is highlighted by the fact that the first harvest, the Omer, rises to the level of the highest worship – it is a public offering that supersedes Shabbat. The Boethusians, who opposed such deferral of Shabbat, certainly were not more pious about the sanctity and observance of Shabbat than those who always kept Shabbat, the Pharisees… They had a toxic idea… to disconnect agriculture from its inherent holiness… separating the higher, esoteric, heavenly worship of the divine from practical, earth-bound agriculture and construction… but the people that collectively knows how to protect its hallows, God’s word that is still with them, also insists on the sanctity of agriculture in Eretz Yisrael, which is also connected to – and extends from – a holy source. Though continued agricultural work is mundane labor and thus forbidden on Shabbat, the offering that initiated this work, the Omer, rises to the level of the Temple holiness, just like other public offerings – the tamid-offerings and the musaf-offerings – and like them supersedes Shabbat.
The mitzva to plant and grow fruits in Eretz Yisrael enables a new and unique understanding of the words of this midrash:
“When you come into the land and plant” – God said to Israel: “Though you will find it filled with all manner of good, do not say, ‘let us settle and not plant,’ rather, take care to plant,” as it says: “and plant all manner of trees for food.” Just as you entered and found what others had planted, you too plant for your children; no one should say, “I am old and will be dead tomorrow. Why should I toil on behalf of others?” … Therefore, man should not desist from planting. Rather, just as he found, he should continue to plant, even when old. God, as it were, said to Israel: “Learn from me – ‘and God planted a garden in the east of Eden’ (Bereishit 2:8). (Midrash Tanchuma, Kedoshim §8)
Perhaps this mitzva of bringing forth the holy fruits of Eretz Yisrael, which makes Erezt Yisrael unique among lands, has an even broader spiritual significance. “Growth” is also a model for transforming potential into the actual, the hidden into the revealed. Our duty is to draw holiness, which originates in hidden spiritual worlds, into our physical, revealed world.
 Boaz was the head of his generation’s sanhedrin, and he nevertheless went to winnow his barley at night by himself and did not rely solely on his workers. See also Bava Batra 91a: “Rabbah b. R. Huna said: Ivtzan is Boaz.” Similarly, Yalkut Shimoni on Rut (4:606) states: “Even though Boaz left and his entire Sanhedrin was filled…” Furthermore, at the time he was eighty years old, as the midrashi (Rut Rabbah 6:2) states: “Boaz was eighty years old and infertile until that righteous woman prayed for him, and he immediately became fertile…”
 R. Kook, Ma'amarei Ha-Re'ayah vol. I p. 179, from Ha-tor no. 23, 5688. See also vol. I p. 177, the essay entitled “Yom Ha-bikurim Zman Matan Torateinu”
 Ibid. He concludes: “The Sages defeated the Boethusians and prevailed over their desire to sever the agricultural basis from its holy context. When the first harvest – the Omer offering – coincided with Shabbat, its status was determined to be that of the fixed schedule of public worship, and those who were led astray learned the wisdom that with God’s right hand, which makes wealth, the Holy Land will give its produce and Eretz Yisrael will be fully rebuilt.