Commentaire sur Le Lévitique 25:19

ונתנה הארץ וגו' וישבתם לבטח עליה AND THE LAND SHALL YIELD [HER PRODUCE AND YE SHALL EAT YOUR FILL], AND ABIDE THEREIN IN SAFETY — The latter words imply that ye shall not have to worry about years (lit., a year) of drought.

ואכלתם לשובע, the produce of the land will prove nutritious. An example of this is the manna when the same quantity, an omer per head, whether for a baby or a fully grown person proved adequate, showing that G’d had imbued it with the nutrients needed by the person eating it. [It was the most individualised diet ever. Ed.] Our sages describe this as an example of food adjusting to the body’s needs after it had come into a person’s entrails. (Torat Kohanim, Bechukotai 1,7) This is also how we can understand that the crops grown in the sixth year of the sh’mittah cycle were able to be sufficient for the people’s needs during the seventh year.

ונתנה הארץ פריה, "And the earth shall yield her fruit, etc." The meaning of "her fruit" is that which corresponds to the potential it has been endowed with. When we observe the earth producing fruit this does not prove that the amount of fruit we observe the earth produce is equivalent to the amount the earth is capable of producing. We find in Ketuvot 112 that a certain sage was angry at the earth and decreed that it be prevented from yielding its fruit. As a result of this curse the earth produced far less than previously. If someone had not seen the amount of fruit that piece of earth produced before the sage cursed it, he would have thought that the amount it produced subsequently was the maximum it was capable of producing.