Reference for Arakhin 23:23

בראשונה במוצאי שביעית מי משכחת לה

And if you should think that [the Sanctuary] was destroyed in the first year [of the seven years' cycle], [consider] there are from the first year of one seven years' cycle to the firs year of another seven years' cycle eight years, and to the first of the next seven years cycle fifteen years? - Said Rabina: It was in the fourteenth year after the year in which the city was smitten.

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