Rashi on Deuteronomy 23:26/רש"י על דברים כ״ג:כ״ו

1כי 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).