כִּ֣י תִקְצֹר֩ קְצִֽירְךָ֨ בְשָׂדֶ֜ךָ וְשָֽׁכַחְתָּ֧ עֹ֣מֶר בַּשָּׂדֶ֗ה לֹ֤א תָשׁוּב֙ לְקַחְתּ֔וֹ לַגֵּ֛ר לַיָּת֥וֹם וְלָאַלְמָנָ֖ה יִהְיֶ֑ה לְמַ֤עַן יְבָרֶכְךָ֙ יְהוָ֣ה אֱלֹהֶ֔יךָ בְּכֹ֖ל מַעֲשֵׂ֥ה יָדֶֽיךָ׃
When thou reapest thy harvest in thy field, and hast forgot a sheaf in the field, thou shalt not go back to fetch it; it shall be for the stranger, for the fatherless, and for the widow; that the LORD thy God may bless thee in all the work of thy hands.
Tosefta Peah
[There are] four gifts [for the poor] from the vineyards: Peret (i.e., grapes that fall during harvesting, see Lev. 19:10, Peah 7:3), forgotten sheaves (Deut. 24:19), peah (Lev. 23:22), and olelet (i.e., defective clusters, see Lev. 19:10, Peah 7:4). [There are] three [gifts for the poor] from field-produce: Gleanings (Lev. 19:9), forgotten sheaves, and peah. [There are] two [gifts for the poor] from fruit trees: forgotten sheaves and peah. [And as to] all of these, they should not [be given as] a favor, and [others] can even take [gifts for the poor given as a favor] from a Jewish poor person from his hand (i.e., since it does not lawfully belong to him in the first place). And [as to] the remainder of the priestly gifts, such as the shankbone and the jawbone and the rough-stomach (see Deut. 18:3), these may be [given as] a favor. And we give [these] to every Kohen that desires [them].
Tosefta Peah
Every olive [tree] that has a [distinguished] name in the field, such as the Olive Tree of Netofah had in its time, and he forgot [to collect its produce from the field], it is not considered forgotten (Peah 7:1). What case are we talking about? About a situation where he had not started with it (i.e., not begun to harvest the tree), but if he had started with it and he forgot it, behold, it is [considered] forgotten, until the time that [the owner has harvested] two seahs (Peah 7:2).