"If you go into your neighbor’s vineyard, you may eat your fill of grapes, as many as you wish, but you shall not put any in your bag. If you go into your neighbor’s standing grain, you may pluck the ears with your hand, but you shall not put a sickle to your neighbor’s standing grain." —Deuteronomy 23:24-25 (ESV)
Brother Will says: This one can be hard to interpret for socialists, but it's harder for capitalists. It says take what you need, and no more. Don't strip the vineyard or the field, because others need to eat.
Here's a modern version to show why it's harder for capitalists: "If you go into a restaurant, eat your fill, as much as you wish, but don't get a doggie bag."
Based on other verses, you may take some home if that's the only way to feed people who couldn't eat otherwise. But essentially, this says what your parents should've taught you: Waste not, want not.
Or it's Louis Blanc again: From each according to ability, to each according to need.