כִּ֣י תִקְצֹר֩ קְצִֽירְךָ֨ בְשָׂדֶ֜ךָ וְשָֽׁכַחְתָּ֧ עֹ֣מֶר בַּשָּׂדֶ֗ה לֹ֤א תָשׁוּב֙ לְקַחְתּ֔וֹ לַגֵּ֛ר לַיָּת֥וֹם וְלָאַלְמָנָ֖ה יִהְיֶ֑ה לְמַ֤עַן יְבָרֶכְךָ֙ יְהוָ֣ה אֱלֹהֶ֔יךָ בְּכֹ֖ל מַעֲשֵׂ֥ה יָדֶֽיךָ׃
네가 밭에서 곡식을 벨 때에 그 한 뭇을 밭에 잊어버렸거든 다시 가서 취하지 말고 객과 고아와 과부를 위하여 버려두라 그리하면 네 하나님 여호와께서 네 손으로 하는 범사에 복을 내리시리라
Sefer HaMitzvot
And that is that He commanded us to leave over the forgotten [produce]. And that is His saying, "and you have forgotten a sheaf in the field, do not turn back to get it; it shall be for the stranger, the fatherless, and the widow" (Deuteronomy 24:19). Behold, His saying, "it shall be," is the command to leave it. And it is a positive commandment; like when He said, "Leave them," - with the gleanings and the corner - it is a positive commandment, as we explained. But by Torah law, it is only practiced in the Land [of Israel]. And the regulations of this commandment have already been explained in Tractate Peah. (See Parashat Ki Tetzeh; Mishneh Torah, Gifts to the Poor 1.)
Sefer HaMitzvot
He prohibited us from taking the forgotten sheaves. And that is His saying, "and you forget a sheaf in the field, you may not return to take it" (Deuteronomy 24:19). And [the commandment of leaving what is forgotten] is practiced both with produce and with [fruit] trees; and is rectified by a positive commandment. For if one transgressed and took it, he is obligated to return it to the poor. And that is His saying, "it shall be for the stranger, the orphan and the widow." And the regulations of this commandment have already been explained in Tractate Peah. And know that the principle with us is that any negative commandment that has a positive commandment [attached to it] - if he fulfills the positive commandment in it, he is not lashed; and if he does not fulfill it, he is lashed. And example of this is that if he harvested the corner, he is not liable for lashes immediately when he harvested. Ratherer he must return the sheaves. And likewise if he threshed them, ground the wheat and kneaded the dough, he must give what was fit for him for [his obligation of] the corner, from the dough. But if it happened that that the wheat got totally lost or it was burnt, he is lashed - as he did not fulfill the positive commandment in it. And all the more so if he negated [the positive commandment] actively - as when he ate all of the wheat. (See Parashat Ki Tetzei; Mishneh Torah, Gifts to the Poor 1.)