Leviticus 25:20

And if ye shall say, What shall we eat the seventh year? behold, we shall not sow, nor gather in our increase:

The verse belongs to the law of the sabbatical year, in which the land was to keep a seventh-year sabbath with no sowing or gathering of its increase in the usual way. It voices the fearful question Israel would ask when told of that rest, what they would eat in the seventh year when they neither sow nor gather. God answered that fear by special interposition, promising under His supervision to bless the sixth year so it would yield provision for three years, sustaining the people until the new harvest came in. The spontaneous growth of the rest year was made available to the poor, strangers, and livestock, including flocks and herds, with the seventh-year growth in particular provided for the poor.

The yearly rest was intended to renew the soil and invigorate worn-out land. The arrangement teaches that God is the Householder and owner of the land and the people are His tenants, and that He cares for His people and for the poor. It teaches that God makes the land productive and blesses it when the people obey, and it embodies a principle of liberality and care for the poor meant to encourage generosity and overcome stinginess and selfishness.