Negative commandment · Lo Ta’aseh #213 of 613
Not to gather individual [fallen grapes]
שלא ללקוט פרט הכרם
The verse · Vayikra 19:10
וְכַרְמְךָ לֹא תְעוֹלֵל וּפֶרֶט כַּרְמְךָ לֹא תְלַקֵּט לֶעָנִי וְלַגֵּר תַּעֲזֹב אֹתָם אֲנִי ה׳ אֱלֹהֵיכֶם
“And thou shalt not glean thy vineyard, neither shalt thou gather the single grapes of thy vineyard; thou shalt leave them for the poor and stranger: I am the Lord your God.”
The Rambam’s words
Not to gather individual [fallen grapes], as [Leviticus, ibid.] states: "Do not gather the individual [fallen grapes] in your vineyard."
שלא ללקוט פרט הכרם, שנאמר "ופרט כרמך לא תלקט" (ויקרא יט,י).
Why · Sefer HaChinuch #223
To not gather the peret of the vineyard
“It is from the roots of the commandment that G-d, blessed be He, wanted that His people that He chose be crowned with every good and dear trait and that they would have a blessed soul and a generous spirit.”
Who & when
“And the content of the commandment, in which place it is practiced and by who — is [all] written above in the commandment of the corner (Sefer HaChinukh 216, 220).”
Where in the Mishneh Torah
Hilchot Gifts to the Poor הלכות מתנות עניים