Reference for Gittin 154:4

אמר ליה רבינא לרב אשי רבא יד דאשה קא קשיא ליה נהי דקני ליה למעשה ידיה ידה גופה מי קני ליה

[we may ask,] how can this be, seeing that the hand of the slave is like that of the master? Only we must suppose that his hand and his deed of emancipation become his simultaneously. So here, her Get and her courtyard become hers simultaneously.

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