English: “You shall make your count for the lamb” — just as the lamb stated regarding Egypt was alive and not slaughtered, so the lamb of the generations is alive and not slaughtered [at the time of enrollment].
On the daf / in context: See the cited source for the full section.
Type of Learning
Gezeirah shavah (seh–seh) — middah of R’ Yishmael’s 13.
What Is Learned
Enrollment on the Pesach is only while the animal is still alive.