Positive Mitzvah 57
Slaughtering the Second Passover Offering
Numbers 9:11 "On the fourteenth day of the second month, at evening, they shall do it"
"It's never too late!"
The Torah declares that a Jew always has a second chance.
If someone was unable to bring the Paschal sacrifice because of impurity (see Positive Mitzvah 74) or because he was too far away to get to the Beit HaMikdash, he is given another opportunity.
This person is commanded to fulfill this obligation, a month later, on the fourteenth day of the month of Iyar.
Positive Mitzvah 56
Eating the Passover Offering
Exodus 12:8 "And they shall eat the meat on that night"
We are commanded to eat the Paschal sacrifice on the night of the fifteenth day of Nisan.
It must be roasted and eaten together with Matzot and bitter herbs.
Positive Mitzvah 58
Eating the second Passover Offering
Numbers 9:11 "And eat it with unleavened bread and bitter herbs"
The second Paschal sacrifice (see above, Positive Mitzvah 57) must be eaten on the night of the fifteenth day of the month of Iyar.
Just like the first, it is to be eaten with matzot and bitter herbs.