ואכלו את הבשר בלילה הזה
שמות יב ח
To eat from the Korban Pesach
So that we should forever remember the miracles Hashem did for us In Egypt.
On the night of the 15th of Nissan.
There are many details about how it is to be eaten.
Males and females.
If you don't do it
Bais Din may force you to do it, as with any other positive commandment.