Reference for Makkot 40:9

והמשחית פאת זקנו: ת"ר פאת זקנו סוף זקנו ואיזהו סוף זקנו שבולת זקנו:

And one who destroys the corners of his beard. etc.: The Rabbis taught in a baraisa "the corner of his beard" refers to the extremities of his beard. And what are the extremities of his beard? The pointy corn-like parts of the beard.

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