DEUT1318 It is positive commandment that an owner should allow the laborer to eat of what he is working at, when it is something that grows from the ground since Scripture says, When you come in to your fellow's vineyard, then you may eat, etc. [this verse]; and it says, When you come into your fellow's standing grain, you may pluck the ears, etc. [this verse]; and by the Oral Tradition it was learned that Scripture speaks here of a laborer. He may eat produce that either was plucked or is attached, whose work has not been completed yet, and by this act [of his labor] the work is completed [to make it bear the obligations of tithes or of hallah]. This means, then, not before the completion of the work nor after the completion of the work, but only during the completion of the work. And for the purpose of returning a loss [lost working time] to the owner, the Sages taught (Talmud, Bava M'tzi'a 91b) that the workers should eat while walking from one furrow to another, and while returning from the winepress [even though they are not actually working then], so that they should not stop their work and sit down to eat, but should rather eat during the labor while they are walking, and us not be idle from their work. If someone is guarding produce attached to the soil, he is not to eat [of it] at all, since a watchman is not like one doing actual labor. If a person is guarding reaped produce, he may eat [of it] not by the law of the Torah, but by the norms of the land.