Midrasz do Psalmów 44:2

It happened that a man had committed a crime for which he had to receive stripes in a court where Raba was the chief justice. Raba had the penalty inflicted on him. He could not endure it, and died. When the government of Sabbor, the king, heard this, they decided to trouble Raba. Whereupon Ifra Ormuzd, mother of King Thapur, said to her son: "I advise you to have nothing to do with the Jews, for all that they request of their God, He grants to them." "What, for example?" asked he. "Why!" said she, "Whenever they pray to God for rain, it rains." "That is only," said he to her, "because they pray in the season when it has to rain. Now, when it is Tamuz (July), when it ought not to rain, let them pray for rain, and you shall see that it will not come." Accordingly she sent to Raba, saying to him: "Direct thy attention to this, and pray to God to send rain." He prayed, and no rain came. Raba then pleaded, saying: "King of the Universe (Ps. 44, 2) O God, we have heard with our ears, our fathers have told us ... in the days of old, etc., but we, with our eyes, have not seen it." Then it rained so much that all the fountains of Mechuza overflowed and the water spread in the streets into the River Tigris. His father appeared to him in a dream and told him: "Is there any other man who has troubled Heaven so much? Go, change thy couch, because of the anger thou hast caused in heaven." On the morrow he found traces of a knife with which his bed had been slashed. R. Papa also ordered a fast. No rain came, however. Meanwhile he felt so weak from fasting, that he took a spoonful of grit and continued to pray. Still, however, no rain came. R. Nachman b. Oshiya then said to him [ironically]: "If the master would partake of another spoonful of grit, then rain would surely come." This mortified him and he was discouraged. He prayed once more, and finally rain came.