What is the meaning of "va'Yisron Eretz ba'Kol Hu"?
Rav Sadya Gaon: The advantage of the land encompasses everything.
Rashi (from Vayikra Rabah 22:3): The Yisron (payment 1 , i.e. punishment) of those who dwell on the land, who are haughty and anger Hashem, is in everything. He uses all messengers to punish them, even mosquitoes, like he did to Titus (Gitin 56b).
Rashi (9) #1: The reward of working the land is greater than all [rewards]. Refer to 5:8:2:1.
Rashi (9) #2: The reward of Yisrael 2 is in all Divrei Torah - Mikra, Mishnah and Talmud.
Ibn Ezra: After commanding about Yir'as Hashem, he teaches about worldly matters - a good job to engage in, that there will not be sin in it. Working the land is the best job.
Rashbam, Rid: All people must work the land, for their sustenance is from it.
Ri Kara: The gain of working the land is in everything - wine, grain, Peros and everything that grows from the ground.
Seforno: The gain that Hashem gets from the land is attained only through the existence of the countries. Tzadikim of the generations, who are important to Him, their nature is civil. Their perfection depends on the Medinos, which supply man with food and clothing; also Tzadikim need these!
Metzudas David: At the time of good, all gain [are fed from] the land, even the lowest. Refer to 5:8:2:8.
Why does it say "Melech l'Sadeh Ne'evad"?
Rav Sadya Gaon: Even the king is subservient to (needs) fields and land. Rashi (9) #1 - if the land produces Peros, he has what to eat. If not, he will starve to death!
Rashi: Hashem became like a worker for Tziyon, to demand payment for those who destroyed it, and reward its builders.
Rashi (9) #2, from Vayikra Rabah 22:1: A king (master of) Mikra and Mishnah is subservient to one who knows Talmud. The latter can arrange for him rulings in Isur v'Heter, Tum'ah and Taharah, and monetary laws.
Ibn Ezra: Even the king, who is above all, must work fields, for his sustenance is from it.
Rashbam: Even the king must command his nation and force them to work the land for his need.
Ri Kara: Even the king needs grain. If he gathered many houses of silver and gold, but has no grain to feed his soldiers 1 , he has no benefit from his silver and gold.
Seforno: People serve the king due to the land, for via the king everyone gets what is proper for him from the land. If not for the king, man would swallow his colleague (Avos 3:2)!
Metzudas David: When [the Medinah's] measure [of sin] is full, and they are punished, matters are reversed. Even the king will lack food, and he will need to work for the owner of the field 2 to do his work, to be fed from the yield of his field.
Why does he discuss feeding his soldiers, and not the king himself? Perhaps he could survive on meat and fish. One cannot do so for a large army, lest he deplete the country's animals, and there is a limit to how much fish can be caught. (PF)
This implies that the king will not have his own fields. Perhaps invaders will seize all the land, even the king's. (PF)
