Midrash su Geremia 48:11

“The king said to the wise men, those knowledgeable about the times, for so was the practice of the king before those learned in custom and law” (Esther 1:13).
Who were they? Rabbi Simon said: This is the tribe of Issachar; that is what is written: “From the children of Issachar, possessors of understanding of the times, to know what Israel should do; [their leaders were two hundred, and all their brethren were at their command]” (I Chronicles 12:33). Rabbi Tanḥuma said: For the [times of] festivals. Rabbi Yosei bar Kotzrat said: For intercalations.¹Determining whether to add a month to the Hebrew calendar in order to keep it synchronized with the solar year. “To know what Israel should do” – that they knew how to cure kiros [lesions]. “Their leaders were two hundred” – these are the two hundred heads of the Sanhedrin that the tribe of Issachar produced. “And all their brethren were at their command” – and everyone agreed that the halakha was in accordance with their opinion as though it were a halakha transmitted to Moses from Sinai.
That wicked one [Aḥashverosh] said to them [his wise men]: ‘Since I decreed that Vashti should enter [the banquet] naked and she did not enter, what is her sentence?’ They said to him: ‘Our master the king, when we were in our homeland, we would consult with the Urim veTumim. Now, we are itinerant,’ and they read this verse before him: “Moav has been tranquil from its youth, and he is settled on his sediments, and was not emptied from vessel to vessel, and into exile he did not go; therefore, his taste has remained in him, and his scent has not dissipated” (Jeremiah 48:11).
“Those close to him [i.e. the relatives for him] were Karshena, Shetar, Admata, Tarshish, Meres, Marsena, and Memukhan, the seven princes of Persia and Media who viewed the face of the king, who were seated first in the kingdom” (Esther 1:14).
He [Aḥashverosh] said to them [the wise men for Issachar]: ‘Are there any of them [the Moabites mentioned in the verse above] here?’ They said to him: ‘Their relatives, that is what is stated: “Those close to him [i.e. the relatives for him] were Karshena, Shetar, Admata, Tarshish, Meres, Marsena, and Memukhan, the seven princes of Persia and…”’ (Esther 1:14).²The midrash does not read verse 13 as the direct continuation of verse 13. Rather, in verse 13, the king turns to the wise men, who are members of the tribe of Issachar according to the midrash. He asks them about people from Moav, and they tell him that the seven wise men listed in verse 14 are all related, and descendants of Moav.
“A righteous person is delivered from trouble, and a wicked one comes in his stead.” (Proverbs 11:8) “A righteous person is delivered from trouble” – that is the tribe of Issachar. “And a wicked one comes in his stead” – these are the seven princes of Persia and Media.
Alternatively: “Those close to him” – it is written: “The mouth of a hypocrite destroys his neighbor, but with knowledge, the just will be delivered” (Proverbs 11:9). “The mouth of a hypocrite destroys his neighbor” – these are the seven princes of Persia and Media; “but with knowledge, the just will be delivered” – that is the role of Issachar.
Alternatively: “Those close to him” – it is written: “A wise man fears and turns away from evil, but the fool becomes enraged and confident” (Proverbs 14:16). “A wise man fears and turns away from evil” – that is the tribe of Issachar; “but the fool becomes enraged and confident” – these are the seven princes of Persia and Media.
Alternatively, “those close to him” – it is written: “The clever one sees evil and hides, but the naive pass and are punished” (Proverbs 22:3). “The clever one sees evil and hides” – that is the tribe of Issachar; “but the naive pass and are punished” – these are the seven princes of Persia and Media.

(Fol. 145b) R. Chiya b. Abba and R. Assi were once sitting before R. Jochanan, while R. Jochanan took a nap. R. Chiya b. Abba asked R. Assi: "Why were the fowls of Babylon so fat?" R. Assi answered him: "Why? Go to the desert of Aza (in Palestine) where I will show thee still fatter ones." Again asked R. Chiya b. Abba: "Why are the Babylonians so joyous during the festivals?" "Because," answered he, "they are poor." "Why are the disciples of Babylon so well dressed?" inquired R. Chiya b. Abba again; "Because," said R. Assi, "they are not so well versed in the Torah as are the Palestinian scholars [and are therefore well dressed to command respect]." "Why do the Babylonians appear to be filthy?" "Because," answered R. Assi, "they eat abominable and creeping things." At that moment R. Jochanan awoke and said to them: "Youngsters! Have I not warned you [to keep in your mind the passage] (Pr. 7, 4.) Say unto wisdom, thou art my sister, which means, if a thing is as certain to thee as the fact that thou canst not marry thine own sister, then say it; otherwise, thou shalt not say it." "Let then the master explain to us some of the above matters," said they. Whereupon R. Jochanan said: "The reason why the fowls of Babylon are so fat is, because they were never driven away from their homes, as it is said (Jer. 48, 11.) Mo'ab was never at ease from his youth, and he was resting on his lees, and was not emptied from vessel to vessel, and had not gone into exile. And whence do we know that the fowls of Palestine were driven from their homes? We are taught that R. Juda said: 'For fifty-two years was the land of Judea isolated so that no man passed through it; as it is said (Ib. 9, 9.) For the mountains will I take up a weeping and wailing, etc., but the fowls of the heavens and the earth are fled; they are gone away, i.e., the numerical value of the word Behema (beast) is fifty-two.' R. Jacob, in the name of Jochanan said: 'All of these came back [to their homes] except only the Calias (tunny fish,' for Rab said that the places of Babylon furnished the water for En-Eitam [by underground pipes and all the fish returned through these pipes] but the tunny-fish, because of its soft backbone, was not able to swim uphill." "The reason that the Babylonians are so joyous during the festivals is because they were not included in the curse which Hoshea pronounced, (Hosh. 2, 13.) And I will cause to cease all her mirth, her festivals, her new moons and her Sabbath and all her appointed feasts. And it is written (Is. 1, 14.) Your new moons and your appointed feasts my soul hateth. They are become a burden unto me!" What is meant by They are become a burden unto me? R. Elazar said: "Thus said the Holy One, praised be He! 'It sufficeth not that Israel sins so much against me, that they trouble me to tell them which hard punishment I should inflict upon them.'" R. Isaac said: "There is not a single festival in Palestine in which reconnoitering troops did not come to Sephoras [and therefore enjoyment was difficult]." R. Chanina said: "There is not one single festival in Palestine in which a general with his suite and strap-bearer [of the Romans] did not come to Tiberia." And the reason that the Babylonian scholars are well-dressed is because they are all strangers. This is what people say, 'At home my name [will give me my position]; abroad, my dress.'"