Reference for Bekhorot 4:64

כל זמן שיד עובד כוכבים באמצע פטורה מן הבכורה

But the Sages say, so long a gentile has a share in it,<span class="x" onmousemove="('comment',' Lit., 'has a hand in the middle'.');">³⁹</span> it is exempt from the law of the first-born.

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