Leviticus 25:1-4 (KJV)
1 And the Lord spake unto Moses in mount Sinai, saying,
2 Speak unto the children of Israel, and say unto them, When ye come into the land which I give you, then shall the land keep a sabbath unto the Lord.
3 Six years thou shalt sow thy field, and six years thou shalt prune thy vineyard, and gather in the fruit thereof;
4 But in the seventh year shall be a sabbath of rest unto the land, a sabbath for the Lord: thou shalt neither sow thy field, nor prune thy vineyard.