תנ״ך אויף ויקרא 19:9

and she said [to herself]: Let me glean [(the gleaning of the ears [leket, viz. Leviticus 19:9])] and let me gather [what was forgotten of] the sheaves [shikchah, viz. Deuteronomy 24:19] after the harvesters. And she came and stood from since the morning until now, and she has just taken a little respite in the house [of the field hands].

You must surely tithe all the produce of your planting, that your field yields on a yearly basis.

When you reap the harvest of your land, you shall not cut completely the corner of your field when you reap. You shall not gather the gleaning of your harvest. You shall leave them for the poor and the proselyte, I am Adonoy, your God.