R. Hisda was holding two [priestly] gifts of oxen in his hand.14 Said he, 'Whoever will come and tell me a new dictum in Rab's name, I will give them to him.' Said Raba b. Mehasia to him, Thus did Rab say: If one makes a gift to his neighbour he must inform him, as it is said, 'that ye may know that I the Lord sanctify you'. Thereupon he gave them to him. Are Rab's dicta so dear to you? asked he. Yes, he replied. That illustrates what Rab said, he rejoined, A garment is precious to its wearer.15 Did Rab indeed say thus! he exclaimed; I rate the second higher than the first, and if I had another [priestly gift] I would give it to you.(It is funny that both of Rava bar Mechasya's citations are on target: first a statement about gifts, and then a statement about things which are dear.)
This incident may have been the impetus for Rava bar Mechasia to begin assembling such a collection of things he had heard from his teacher.
Rav was a first generation Amora, which would make Rav Chama bar Guria a second generation Amora and Rava bar Mechasia a third generation Amora, it would seem.
We see that Rav Chisda coexisted with Rava bar Mechasia, first because he interacts with Rav Chisda in the story above, and less so, but interesting to note, because Rav Chisda clarifies one of his statements:
Raba b. Mehasia also said in the name of R. Hama b. Goria in Rab's name: Fasting is as potent against a dream as fire against tow.10 Said R. Hisda: Providing it is on that very day. R. Joseph added: And even on the Sabbath.11Rav Chisda was a third generation Amora himself. Rav Chisda lived in Bavel, and was first a student of Rav. After Rav's death, he studied under Rav Huna (second generation Amora) in Sura. They had a parting of ways:
The separation was brought about by a question from Rav Chisda as to the obligations of a disciple toward a master to whom he is indispensable. Rav Huna saw the point and said, "Chisda, I do not need thee; it is thou that needst me!". Forty years passed before they became reconciled. Rav Chisda nevertheless held Rav Huna in great esteem, and although he had established a school built at his own expense in Mata Mehasya four years before Rav Huna's death, he never published any decision during the Rav Huna's lifetime.Also,
Rav Chisda also presided over the Academy of Sura for ten years following the death of Rav Yehuda, or following the death of Rav Huna, according to Abraham ibn Daud.So he presided over both the academy of Sura and of the nearby Mata Mechasya. They are NOT the same place.
I have to wonder whether Rava bar Mechasia was not the son of someone named Mechasia, but was rather someone named Rava (in other words, Rabbi Abba) who lived in the town of Mechasya.
We see Rav Ashi, a sixth-generation Amora, who reopened the academy of Sura after Rav Chisda's death, pay heed to two statements of Rava bar Mechasia. (Regarding dreams and synagogue height.) Rav Ashi died in 427 CE.
Consider this gemara:
Raba b. Mehasia also said in the name of R. Hama b. Goria in Rab's name: Every city whose roofs are higher than the synagogue will ultimately be destroyed, as it is said, to exalt the house of our God, and to repair the ruins thereof.2 Yet that refers only to houses; but as for towers and turrets, we have no objection. R. Ashi said: I achieved for the town of Mehasia3 that it was not destroyed.4 But it was destroyed!5 — It was not destroyed as a result of that sin.I would posit that when Rav Ashi the statement, it was absolutely true. And where the setama degemara objects and responds that it was indeed destroyed, but for a different sin, that was at some later time.
If we look at the footnote in Soncino, we can get some idea as to the date of this destruction:
There is evidence that Mehasia was still standing in the second half of the seventh; consequently the destruction mentioned here must have been a partial one; ibid. p. 290.Perhaps we are not talking about partial destruction, though. Perhaps whoever wrote this setama degemara was quite late. There is evidence of even Geonic insertions into the Talmud, and maybe this is one such insertion.