[5a bottom] Gemarah: The Pesach offering has a set time to be brought within, and if that time is missed it is rejected from ever being accepted as a Korban (sacrifice) again.
T’s lesson: There are things in life that are time bound and require a person to fulfill at the exact specific moment. Shacharis (morning prayers) may not be said in the afternoon, and Minchah (afternoon prayers) may not be said in the morning. Shabbos is only celebrated on the seventh day, and Tefillin is only worn in the morning. It is crucial to do Mitzvos at their appointed times so as not to lose out on the exact opportunity to serve Hashem.