The 170th mitzvah is that we are commanded to listen to the sound of the shofar on the first1 day of Tishrei [Rosh Hashanah].
The source of this commandment is G‑d's statement2 regarding that day, "It shall be a day of sounding the horn."
The details of this mitzvah are explained in tractate Rosh Hashanah.
Women are not obligated in this mitzvah.3