Peah
ויקרא יט,ט: ובְקֻצְרְ כ ם א ת־קְצִיר אַרְ צְכ ם לֹא תְ כַל ה פְאַת שָׂדְךָ לִקְצֹר וְל ק ט קְצִירְ ךָ לֹא תְ לַקֵּט :
Baal HaTurim: The verse contains four words of the root קצר (harvesting). This corresponds to the four exclusions of a field from the laws of Peah where the field has been: (1) harvested by thieves; (2) gnawed by ants; (3) broken by the wind; (4) eaten by animals.
The term וקצרכם (your reaping) indicates your field has be reaped with your intention and approval. The Mishneh (Peah 2:7) includes a fifth category of a field harvested by non-Jews. The commentators explain that the non-Jew harvested the field for their own use or a convert harvested the field prior to conversion (which may be why not classified with the other four).
