Exodus 23:10-12

And six years thou shalt sow thy land, and shalt gather in the increase thereof: but the seventh year thou shalt let it rest and lie fallow; that the poor of thy people may eat: and what they leave the beast of the field shall eat. In like manner thou shalt deal with thy vineyard, and with thy oliveyard. Six days thou shalt do thy work, and on the seventh day thou shalt rest; that thine ox and thine ass may have rest, and the son of thy handmaid, and the sojourner, may be refreshed.