Leviticus 25:21,22

Then I will command my blessing upon you in the sixth year, and it shall bring forth fruit for three years.

I will command my blessing ... A provision was made, by the special interposition of God, to supply the deficiency of food which would otherwise have resulted from the suspension of all labour during the Sabbatic year. The sixth year was to yield a miraculous supply for three continuous years. And the remark is applicable to the year of Jubilee as well as the Sabbatic year. (See allusions to this extraordinary provision in 2 Kings 19:29; Isaiah 37:30.) None but a legislator who was conscious of acting under divine authority would have staked his character on so singular an enactment as that of the Sabbatic year; and none but a people who had witnessed the fulfillment of the divine promise would have been induced to suspend their agricultural preparations on a recurrence of a periodical Jubilee.