Megillah, Chapter Two, Mishnah Six
This mishnah is the complement to yesterdays mishnah. It teaches that mitzvoth which must be performed at night can be performed all night.
1) The whole night is valid for reaping the Omer and for burning fat and limbs [on the altar].
2) This is the general principle: any matter whose commandment is during the day, is valid all day and any matter whose commandment is at night is valid all night.
Section one: There are two mitzvoth listed here that must be done at night. The first is reaping the Omer, the barley offering which is brought from the second day of Pesah through Shavuot (Leviticus 23:10). The second is putting on the altar fat and limbs that had not been burned during the day.
Section two: This general principle illustrates that which we learned in the last two mishnayot.