The 124th mitzvah is that we are commanded to leave over for the poor those grapes that have become detached and fall during the harvesting process.

The source of this commandment is G‑d's statement,1 "Do not pick up peret (individual2 fallen grapes) in your vineyard. You must leave them for the poor and the stranger."

The details of this mitzvah are also explained in tractate Pe'ah.3

The Biblical prohibition applies only in Eretz Yisroel.4