Leviticus 25:21-23

21then I will command my blessing upon you in the sixth year, that it may bring forth produce for three years;

22and ye shall sow in the eighth year, and ye shall eat of the old fruit until the ninth year; until her produce come in, ye shall eat the old.

23And the land shall not be sold for ever; for the land is mine; for ye are strangers and sojourners with me.