'Gleaning Grapes' in the Bible

Yet gleaning grapes shall be left in it, as the shaking of an olive tree, two or three berries in the top of the uppermost bough, four or five in the outmost fruitful branches thereof, saith the LORD God of Israel.

When thus it shall be in the midst of the land among the people, there shall be as the shaking of an olive tree, and as the gleaning grapes when the vintage is done.

If grapegatherers come to thee, would they not leave some gleaning grapes? if thieves by night, they will destroy till they have enough.

If thieves came to thee, if robbers by night (how art thou cut off!), would they not steal only till they had enough? if grape-gatherers came to thee, would they not leave some gleaning grapes?