Charles Ellicott Commentary Leviticus 26:20

"and your strength shall be spent in vain; for your land shall not yield its increase, neither shall the trees of the land yield their fruit." — Leviticus 26:20 (ASV)

And your strength shall be spent in vain. —That is, with the heaven over them as metal, their labor expended in plowing, digging, and sowing will be perfectly useless.

Your land shall not yield her increase, as no amount of human labor will make up for the lack of rain. In Deuteronomy 11:17, where the same punishment is threatened, and the same phrase is used, the Authorized Version unnecessarily obliterates the identity of the words in the original by rendering them "the land yield not her fruit."