רב אחא מדפתי

Rav Acha of Difti was an amora of Bavel of the sixth generation, among the chachamim of the yeshivah of Sura at Mata Mechasya. His statements are brought many times in the Talmud Bavli, most often in give and take with his colleague Ravina.

After Rav Ashi was niftar the yeshivah of Sura was headed in turn by Rav Yeimar, Rav Idi bar Avin the Second and Rav Nachman bar Rav Huna, and when the last of these was niftar the chachamim took counsel to appoint a successor. The Gemara relates that Mar bar Rav Ashi, walking in the market of Mechoza, heard a fool calling out that the rosh yeshivah to be appointed at Mata Mechasya signs himself Tavyomi — which was his own manner of signing — and he set out for the yeshivah. In the meantime the chachamim had settled on Rav Acha of Difti and sent two talmidim to seek Mar bar Rav Ashi’s agreement to the appointment. He kept the pair with him; another pair was sent and he kept them too, and so on until ten had gathered, whereupon he opened and expounded, since a Kallah derashah is not begun without ten — and by that he became rosh yeshivah himself.

Hearing of it, Rav Acha said that those to whom Heaven brings ill are not soon brought good, and those to whom Heaven brings good are not soon brought ill. One explanation given for the episode connects it to the teaching that a chacham appointed rosh yeshivah has all his sins forgiven with the appointment, which accounts both for Mar bar Rav Ashi’s particular interest in the position and for Rav Acha’s disappointment.