The 127th mitzvah is that we are commanded to separate ma'aser from produce which grows from the ground.
The source of this commandment is G‑d's statement,1 "[The inheritance I am giving the Levites shall consist of] the ma'aser of the Jewish people which they shall separate."
The verse itself explains that ma'aser is given to the Levites.
The details of this mitzvah are explained in tractate Ma'aseros.
This is called ma'aser rishon, and is a Biblical requirement only in Eretz Yisroel.2
