Reference for Makkot 29:10

ואימא ואם אינו ענין לפניו דמוציא שם רע תנהו ענין לאחריו דידיה דלא לקי

But you can say, If it is not applicable before the Motzei Shem Rah [divorces his wife] apply it afterwards by itself [Motzei Shem Rah] that he does not recieve malkus for divorcing his wife [because he can remarry her].

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