Baal HaTurim on Shemot 12:4-5 of Parashat Bo
12:4-5 ish lefi ochlo - Everyone according to what he eats.
The gematria of this phrase (488) is equal to that of echol kezyit, Eat an olive-sized portion.  This tells you that if one ate an olive-sized portion one has fulfilled the obligation to partake of the pesach-offering (Peirush HaRokeach; Resachim 91a; Rambam, Hilchot Korban Pesach 8:3).
tachosu al-haseh.  seh tamim - You shall count for the lamb/kid.  An unblemished lamb/kid.
(The term seh here refers to the young of both sheep and goats (see v5).  In the absence of a precise English equivalent, the translation "lamb/kid" is used.)
The lamb/kid is mentioned twice, indicating that two are necessary: one (a male) for the pesach-offering, and one for the chagigah-offering which accompanied it.
(The chagigah-offering was brought and eaten as a prelude to the pesach-offering so that the pesach-offering would be eaten on a full stomach.)
The word seh, lamb/kid, appears six times in this passage - if we count from the sheep [and from the goats].  (The word seh appears twice in v3, twice in v4, and once in v5.  If we add the phrase from the sheep and from the goats (v5), which defines the term seh, we have six appearances of the animal's name.)  This is an allusion to the law:  [We keep] no less than six inspected lambs in the Chamber of the Lambs (Arachin 13a).
(The Chamber of the Lambs is a room in the Temple where the lambs for the tamid (daily continual-offering) are kept.  The Temple authorities must keep at least six lambs inspected and found to be free of disqualifying blemishes on hand at all times.)
12:8 Ve'achulu et-habasar - They shall eat the flesh.
The verse begins with eating [They shall eat the flesh] and ends with eating.