mah inyan naaseh v'nishma to the farmer observing shemita?

Barchu Hashem malachav giborei koach osei devaro lishoma kol d'varo (Teh 103:20).  The angels are described as serving G-d through their actions simply for the privilige of hearing what Hashem says, for no other reward (Metzudas David, Ibn Ezra).   

Chazal focus on the fact that the angels put action before hearing/understanding, and apply the pasuk to Klal Yisrael's acceptance of the Torah by saying naaseh v'nishma:

 א״ר ישמעאל בשעה שהקדימו ישראל נעשה לנשמע יצאה בת קול ואמרה להם בני מי גלה לכם רז זה שמלאכי השרת משתמשים בו דכתיב ברכו ה׳ מלאכיו גבורי כח עושי דברו וגו׳, ברישא עושי והדר לשמוע.

Yet Chazal also darshen then same pasuk as referring to the farmers who are giborei koach and manage to keep shemita for a whole year:

רבי יצחק נפחא אמר אלו שומרי שביעית, בנוכהג שבעולם אדם עושה מצוה ליום אחד לשבת אחד לחדש אחד שמא (לשאר) [לכל] ימות השנה ודין חמי חקליה ביירא כרמיה ביירא ושתיק יש לך גבור חיל גדול מזה. נאמר כאן עושי דברו ונאמר להלן וזה דבר השמטה מה להלן שביעית אף כאן שביעית, ושנו רבותינו אי זהו גבור הכובש את יצרו, 

Mah inyan shemita eitzel har Sinai?  So which is it -- are talking about naaseh v'nishma or about farmers?  

Sefas Emes (5646) explains that the machlokes we discussed last week (Brachos 35) between R"Y and Rashb"Y --  R"Y holds a person has to plant when its time to plant, plow when its time to plow, harvest when its time to harvest, but Rashb"Y said if you do that, what becomes of talmud Torah? -- is only a question after the cheit of Adam haRishon.  Everyone agrees that the ideal situation, the kodem ha'cheit, the kodem "b'ze'as apech tocham lechem," is only Torah.  

When Klal Yisrael stood at Sinai, they were like malachim, like Adam before the cheit.  No misa, no need for food -- lo nitna Torah elah l'ochlei ha'mon, the food of malachim -- totally focused on the one goal of fulfilling ratzon Hashem.

That situation did not last, but there is a m'ein that survived.  Once a week we put down the shovel and the plow, we put away our iphone and computer, and we come back to that level of Torah only, like we were when we stood at Sinai like angels.  We become like the ochlei ha'mon, but in this case it's ochlei cholent.  

The farmer goes a step further.  He puts everything aside not just for a day, or a month, but for an entire year he lives without "b'ze'as apecha," like Adam before the cheit  "V'tzivisi es birchasi..." we all know the vort from R' Zusha, that it's only those who ask "mah nochal" who need the "tzivisi," but otherwise during shemita the farmers is sustained derech nes, ochel min ha'shamayim, just like the ochlei ha'mon.

Eilu v'eilu, the pasuk "osei devaro..." is talking about maamad Har Sinai and also about observing shemita because they are one and the same idea.  Shemita is a return (the "v'shavtem... el achuzaso" of yoveil is the same return to one's shoresh), albeit temporarily, to that ideal achieved at Sinai, of life as it was in Eden.