Our Gemara relates an unusual story about Ilfa, one of the first generation amoraim in the Land of Israel. Ilfa attached himself to a ship’s mast and announced that if anyone presented him with a teaching that appeared in the baraitot of Rabbi Ḥiyya and Rabbi Oshaya, he would show a source from the Mishna from which this teaching could be understood (i.e. that all of the traditions that appeared in the were included in the Mishna). Furthermore, he said if he was unable to do so he would throw himself into the sea. The Gemara relates that there were those who took Ilfa up on his challenge, and that he was able to successfully respond to those challenges.
As noted, Ilfa – who is referred to in the Talmud Yerushalmi as Hilfa or Hilfai – lived in Israel during the period of the first generation of’im. In his youth, he was among the students who learned with Rabbi Yehuda HaNasi, after which he and his younger colleague, Rabbi Yohanan, studied together. These were economically difficult times in Israel and the two of them decided to leave their studies and embark on business ventures. As it turned out, Rabbi Yohanan changed his mind and returned to the study hall, while Ilfa left – apparently he left Israel – to try his hand at business.
During Ilfa’s absence, the position of Rosh Yeshiva in the academy in Israel became vacant, and Rabbi Yohanan was chosen to lead it. Upon his return to Israel, there was speculation that Ilfa had been rejected for the post because he was not truly a capable scholar. This brought him to defend his honor with displays of prowess like the one described in the Gemara. The Yerushalmi describes a similar story, where Ilfa stood on the banks of a river and announced that he should be thrown into the river if he did not successfully make his case.
Ilfa’s teachings are found in both the Talmud Bavli and Yerushalmi. We even find Rabbi Yohanan quoting his teachings.