Halakhah zu Dewarim 22:25

That is that He commanded us that an employee eat from the thing he is working upon, at the time of his work - when the thing is attached to the ground. And that is His, may He be exalted, saying, "When you enter the vineyard of [...] When you enter the standing grainstalks of" (Deuteronomy 22:25-26). And it has already been explained in the Gemara, Metzia (Bava Metzia 87b) that we learn from these two verses that a man may eat while at work from what is attached to the ground; and that one verse would not suffice without its fellow [being together] with it. [This is] as we explained earlier here (Sefer HaMitzvot, Positive Commandments, 140), when they said, "Until both verses are stated. And, if not, we would not have understood [it]." Hence the content of this positive commandment - meaning the employee's eating from that which is connected - arose from two verses. And in the explanation (Bava Metzia 87a), they said, "These may eat, from the Torah, etc." And the regulations of this commandment have already been explained in Chapter 7 of [Bava] Metzia (See Parashat Ki Tetzei; Mishneh Torah, Hiring 12).