כִּ֤י תָבֹא֙ בְּקָמַ֣ת רֵעֶ֔ךָ וְקָטַפְתָּ֥ מְלִילֹ֖ת בְּיָדֶ֑ךָ וְחֶרְמֵשׁ֙ לֹ֣א תָנִ֔יף עַ֖ל קָמַ֥ת רֵעֶֽךָ׃ (ס)
Quand tu entreras dans les blés de ton prochain, tu pourras, avec la main, arracher des épis; mais tu ne porteras point la faucille sur les blés de ton prochain.
Rashi
כי תבא בקמת רעך WHEN THOU COMEST INTO THE STANDING CORN OF THY FELLOW MAN [THOU MAYEST PLUCK THE EARS WITH THINE HAND] — In this case too, Scripture is referring to a labourer in the field (cf. Sifrei Devarim 267:1; Bava Metzia 87b).
Ibn Ezra
into your fellowman’s grain field in order to harvest the grain (the passage you must not lift up a sickle caused the Dissenters to claim that permission is extended to wayfarers as well).
Siftei Chakhamim
With this, as well, Scripture refers to the laborer. Because it is written, “But do not lift a sickle.” This indicates that Scripture is referring only to the time of harvest, [a time] when you reap and place into the owner’s receptacle. But, if he is hired to plow or for some other activity, he may not eat. This indicates that Scripture refers to the laborer.