Reference for Berakhot 119:8

היכי דמי כגון דשקל בדקא בארעיה אף על גב דטבא היא לדידיה דמסקא ארעא שירטון ושבחא השתא מיהא רעה היא:

How is this to be understood? — For instance, if a freshet flooded his land. Although it is [eventually] a good thing for him, because his land is covered with alluvium and becomes more fertile, nevertheless for the time being it is evil.

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