According to the Mishnah on today’s daf (=page), it is possible for a single activity to have several consequences, and, under those circumstances, for a person to become liable for the punishment of malkot (lashes) a number of times. Thus, a person who was plowing a single furrow may end up with eight separate punishments: (1) if the two animals were an ox and a donkey (see Devarim 22:10) and (2-3) both animals were consecrated to the Temple, and (4) the seeds were forbidden mixtures and (5) this was done during the Sabbatical year when plowing is forbidden. Furthermore (6) it was Yom Tov when work is forbidden and the individual is (7) a kohen and (8) a nazir and the furrow was being dug in a cemetery, where it is forbidden for them to enter.
The Gemara relates that this Mishnah was quoted in the context of a discussion between Rabbi Yannai and Rabbi Yohanan, when Rabbi Yannai taught that when dealing with kil’ayim – forbidden mixtures of planted seeds – even simply covering them with dirt would be forbidden as it is part of the planting process. Rabbi Yohanan argues that this did not need to be taught, since it was clear from our Mishnah that that ruling is correct, since if someone merely plowed over the seeds that is listed as an act that is forbidden. Rabbi Yannai accepted Rabbi Yohanan’s point, but told him that “had he not lifted that haspa (=pottery shard), he would not have discovered the jewel underneath it” (that is to say, it was only because of his teaching that Rabbi Yohanan realized the significance of the Mishnah).
The analogy of the clay shard and the jewel can be understood simply as the difference between the valueless covering and the valuable hidden object. Tosafot, however, point to a more exact meaning, quoting Rabbenu Tam as explaining that on the ocean floor there are large stones that look like pottery shards, and jewels can be found underneath them. Some suggest that the word haspa is, in fact, the name of the sea shell in which pearls are found, and the idea conveyed by Rabbi Yohanan is that if someone does not pay close attention to the simple sea shell, he will not succeed in finding the pearl.