כִּ֣י תִקְצֹר֩ קְצִֽירְךָ֨ בְשָׂדֶ֜ךָ וְשָֽׁכַחְתָּ֧ עֹ֣מֶר בַּשָּׂדֶ֗ה לֹ֤א תָשׁוּב֙ לְקַחְתּ֔וֹ לַגֵּ֛ר לַיָּת֥וֹם וְלָאַלְמָנָ֖ה יִהְיֶ֑ה לְמַ֤עַן יְבָרֶכְךָ֙ יְהוָ֣ה אֱלֹהֶ֔יךָ בְּכֹ֖ל מַעֲשֵׂ֥ה יָדֶֽיךָ׃
אַז דו װעסט שנײַדן דײַן שניט אין פֿעלד, און װעסט פֿאַרגעסן אַ גאַרב אין פֿעלד, זאָלסטו זיך ניט אומקערן זי צו נעמען; פֿאַרן פֿרעמדן, פֿאַרן יתום, און פֿאַר דער אַלמנה, זאָל עס זײַן; כּדי ה׳ דײַן גאָט זאָל דיך בענטשן אין יעטװעדער טואונג פֿון דײַנע הענט.
Rashi
ושכחת עמר [WHEN THOU REAPEST THY HARVEST IN THY FIELD] AND HAST FORGOT A SHEAF … [THOU SHALT NOT RETURN TO TAKE IT] — a sheaf, but not a stack of corn (Sifrei Devarim 283:1). Hence they (the Rabbis) said, “A sheaf that contains two Seahs of grain which one has forgotten in the field, does not come under the term of שכחה (a forgotten sheaf)” (Mishnah Peah 6:6).
Chizkuni
לגר, ליתום, ולאלמנה יהיה, למען יברכך ה, “(these sheaves the owner appears to have forgotten) are rightfully the stranger’s, the orphan’s and the widow’s, in order that the Lord will bless you (also in the future).” You will not be deprived of anything by not going back to pick up what you left behind by mistake.
Ibn Ezra
in order that He will bless you for you gave of what you only imagine to be yours; but God will give to you of that which is truly His.
Rabbeinu Bahya
צוטריטלעך נאָר פֿאַר פּרעמיום־מיטגלידערSiftei Chakhamim
צוטריטלעך נאָר פֿאַר פּרעמיום־מיטגלידערRav Hirsch
צוטריטלעך נאָר פֿאַר פּרעמיום־מיטגלידערRashi
בשדה [AND HAST FORGOT …] IN THE FIELD — This apparently redundant word (it has just stated בשדך) is intended to include under this law forgotten “standing corn” (קמה) — that one has forgotten to cut down part of it (Sifrei Devarim 283:2).
Siftei Chakhamim
צוטריטלעך נאָר פֿאַר פּרעמיום־מיטגלידערRav Hirsch
צוטריטלעך נאָר פֿאַר פּרעמיום־מיטגלידערRashi
לא תשוב לקחתו THOU SHALT NOT GO BACK TO TAKE IT — Hence they (the Rabbis) said: A sheaf that is behind him is considered as שכחה, that which is in front of him is not considered שכחה, for the expression “thou shalt not go back [to take it]” is not applicable to it (Mishnah Peah 6:4; Bava Metzia 11a).