(Devarim 24:19) "When you reap your harvest in the field, if you forget a sheaf in the field, do not return to take it": to exclude its being reaped by robbers, ravaged by ants, or broken by the wind or by beasts.
"your harvest": to exclude that which appertains to the Temple and to gentiles — whence they ruled: A gentile who reaped his field and then became a convert is exempt from leket, shikchah, and peah. R. Yehudah makes him liable for shikchah; for shikchah obtains only at the time of sheaving, (at which time he was a Jew.)
R. Yossi Haglili says: (It is written) "When you reap your harvest in your field and you forget a sheaf": Wherever your reaping obtains, shikchah ("forgetting") obtains in the sheaves; wherever your reaping does not obtain, shikchah does not obtain in the sheaves — which is to say that if the Temple reaped (the field) and an Israelite bought it, he is exempt (from shikchah); if a gentile reaped (the field) and an Israelite bought it, he is exempt.
"in your field": excluding (from shikchah) one who makes sheaves in his neighbor's field. These are the words of R. Meir; the sages rule it liable (for shikchah).
(דברים כד יט) כִּי תִקְצֹר קְצִירְךָ, פְּרָט לְשֶׁקְּצָרוּהוּ לִיסְטִים וְקִרְסְמוּהוּ נְמָלִים וּשְׁבָרַתּוּ הָרוּחַ אוֹ בְהֵמָה.
(Devarim 24:19) "When you reap your harvest in the field, if you forget a sheaf in the field, do not return to take it": to exclude its being reaped by robbers, ravaged by ants, or broken by the wind or by beasts.
קְצִירְךָ, פְּרָט לְשֶׁקְּצָרוּהוּ גּוֹיִם. מִכָּן אָמְרוּ: נָכְרִי שֶׁקָּצַר אֶת שָׂדֵהוּ וְאַחַר כָּךְ נִתְגַּיֵּר, פָּטוּר מִן הַלֶּקֶט וּמִן הַשִּׁכְחָה וּמִן הַפֵּאָה. רַבִּי יְהוּדָה מְחַיֵּב בַּשִּׁכְחָה, שֶׁאֵין שִׁכְחָה אֶלָּא בִּשְׁעַת הָעִמּוּר. קְצִירְךָ, פְּרָט לַאֲחֵרִים. קְצִירְךָ, פְּרָט לְהֶקְדֵּשׁ. כְּשֶׁתִּמְצֵי אוֹמֵר: קָצַר הֶקְדֵּשׁ וְלָקַח יִשְׂרָאֵל, פְּטוּרָה. קָצַר גּוֹי וְלָקַח יִשְׂרָאֵל, פְּטוּרָה.
"your harvest": to exclude that which appertains to the Temple and to gentiles — whence they ruled: A gentile who reaped his field and then became a convert is exempt from leket, shikchah, and peah. R. Yehudah makes him liable for shikchah; for shikchah obtains only at the time of sheaving, (at which time he was a Jew.)
רַבִּי יוֹסֵי הַגְּלִילִי אוֹמֵר: מִכְּלַל שֶׁנֶּאֱמַר (דברים כד יט): כִּי תִקְצֹר קְצִירְךָ בְשָׂדֶךָ וְשָׁכַחְתָּ עֹמֶר, כָּל זְמַן שֶׁיֵּשׁ לוֹ קָצִיר יֵשׁ לוֹ עֹמֶר וְיֵשׁ לוֹ שִׁכְחָה, כָּל זְמַן שֶׁאֵין לוֹ קָצִיר אֵין לוֹ עֹמֶר וְאֵין לוֹ שִׁכְחָה. כְּשֶׁתִּמְצֵי אוֹמֵר: קָצַר הֶקְדֵּשׁ וְלָקַח יִשְׂרָאֵל פְּטוּרָה, קָצַר גּוֹי וְלָקַח יִשְׂרָאֵל פְּטוּרָה.
R. Yossi Haglili says: (It is written) "When you reap your harvest in your field and you forget a sheaf": Wherever your reaping obtains, shikchah ("forgetting") obtains in the sheaves; wherever your reaping does not obtain, shikchah does not obtain in the sheaves — which is to say that if the Temple reaped (the field) and an Israelite bought it, he is exempt (from shikchah); if a gentile reaped (the field) and an Israelite bought it, he is exempt.
בְשָׂדֶךָ, פְּרָט לִמְעַמֵּר בִּשְׂדֵה חֲבֵרוֹ, דִּבְרֵי רַבִּי מֵאִיר; וַחֲכָמִים מְחַיְּבִים. מִכָּן אַתָּה אוֹמֵר: הָעֹמֶר שֶׁשְּׁכָחוּהוּ פּוֹעֲלִים וְלֹא שְׁכָחוֹ בַּעַל הַבַּיִת, שְׁכָחוֹ בַּעַל הַבַּיִת וְלֹא שְׁכָחוּהוּ פּוֹעֲלִים, עָמְדוּ הָעֲנִיִּים בְּפָנָיו אוֹ שֶׁחִפּוּהוּ בְקַשׁ, הֲרֵי זֶה אֵינוֹ שִׁכְחָה.
"in your field": excluding (from shikchah) one who makes sheaves in his neighbor's field. These are the words of R. Meir; the sages rule it liable (for shikchah).