And the Levi shall come, for he has no portion or inheritance with you, and the stranger and the orphan and the widow who are within your gates, and they shall eat and be satisfied, in order that Hashem your God may bless you in all the work of your hand that you do.
English: "For he has no portion" — when he has no portion and you have a portion, one is obligated in ma’aser; this excludes ownerless produce, leket, shikhecha and pe’ah, in which he too has a share, and which are therefore exempt from ma’aser.
On the daf / in context: Produce in which the poor already possess a legal right is not subject to the further obligation of tithing.
Type of Learning
Derash on the verse (Yerushalmi) — ownerless agricultural gifts are exempt from ma’aser.
What Is Learned
Leket, shikhecha, pe’ah and other ownerless produce are exempt from ma’aser because the poor already share in them.