Two daily offerings were brought in the Temple every, single day – the tamid shel shaḥar and the tamid shel bein ha-arbayim (the daily morning sacrifice and the daily afternoon sacrifice). Accompanying these sacrifices was the ketoret – the incense offering – that was brought both morning and afternoon.
If the korban tamid was not brought in the morning, the Tanna Kamma permits the afternoon korban tamid to be offered at its proper time. Rabbi Shimon only allows the kohanim to bring the korban tamid in the afternoon if it had been neglected in the morning by accident. If, however, they had purposefully neglected to bring it in the morning, they cannot bring the afternoon sacrifice.
On today’s daf, Rava explains Rabbi Shimon’s position as meaning that the kohanim who neglected the morning korban tamid are punished, but the sacrifice is still brought, albeit by other kohanim.
If the ketoret was not brought in the morning, the Tanna Kamma permits the afternoon ketoret to be brought in the afternoon as usual. Rabbi Shimon agrees that it should be brought, but insists that the full amount of the daily ketoret must be brought – both the morning half and the afternoon half.
In this case the Gemara explains Rabbi Shimon’s position, that since the ketoret was unusual and there was a tradition that the person who brought it would become wealthy, there was no need to establish a punishment for kohanim who did not bring it, since it was never neglected.
Two explanations are offered by Rashi as to why the daily ketoret was considered “unusual.” One is that the korban tamid is actually a form of a common korban ola (a burnt offering) while the ketoret was unique and limited to the twice daily offerings. Another approach is that according to the Gemara in Yoma (daf 26a ), no kohen would merit the service of offering the ketoret more than one time in his life.