The obligatory sacrifices described in Sefer Vayikra were brought in the Tabernacle in the desert, but their ultimate destiny was to be brought in the Temple in Israel. What was their status when the Children of Israel first entered the Land of Israel?
According to the Mishna (daf 112) a person would not be held liable for bringing sacrifices outside of the precincts of the Temple, if they are brought before or after the appropriate time (e.g. torim – turtledoves – that had not yet reached adulthood, or benei yona – pigeons – that have become adults, see daf 68). Rabbi Shimon disagrees and rules that someone who brings a sacrifice whose time to be brought has yet to have occurred will be subject to malkot – lashes – for his transgression.
The Gemara on today’s daf searches for a source for Rabbi Shimon’s position, and Rabbi Ile’a quotes Reish Lakish as learning it from a passage in Sefer (12:8-9). According to this pasuk, the Torah forbids the people from bringing sacrifices the way they were brought in the desert. Rabbi Shimon’s interpretation of the command is that upon entering the Land of Israel, the Jewish people could no longer continue bringing communal sacrifices as they had done in the desert; only personal sacrifices consisting of nedarim and nedavot – voluntary sacrifices – could be brought in the Tabernacle when it was first erected in Israel (in Gilgal). This reading of the pasuk was understood to mean that this situation was to remain in force until the time that the people arrived at the menuḥa – “the resting place,” i.e. Shiloh – and the naḥala – “the inheritance,” i.e. Jerusalem. Only then could obligatory sacrifices be brought as they were in the Tabernacle in the desert.
It was based on this that Rabbi Shimon reasoned that since it was forbidden to bring sacrifices in Gigal prior to the establishment of the mishkan in Shiloh, we learn the principle that meḥusar zeman – a sacrifice whose time had not yet arrived – cannot be brought outside the Tabernacle. Similarly there is a prohibition in effect against bringing sacrifices outside the Temple when they could be brought at a later date.