Deuteronomy 24:20

When thou beatest thine olive tree] In gathering olives the fruit is brought to the ground either by shaking the boughs or beating them with a long palm branch. At the present time the trees are beaten on a certain day announced by a crier, after which the poor are allowed to glean what is left. A similar permission holds good in the case of vineyards and cornfields: see on Leviticus 19:9. Gleaning is a beautiful and kindly custom still surviving to some extent in Palestine, but fast disappearing before the introduction of modern methods of harvesting, which are not unnaturally regarded with disfavour by the poorer classes.