Halakhah for Sanhedrin 90:13
רוצח הא דאמרן גואל הדם מאי היא דתניא (במדבר לה, כא) גואל הדם ימית את הרוצח מצוה בגואל הדם ומניין שאם אין לו גואל שב"ד מעמידין לו גואל שנאמר (במדבר לה, יט) בפגעו בו מכל מקום
— There it is different, for Scripture says, He shall surely be put to death.<span class="x" onmousemove="('comment',' [H]. The infinitive strengthens the idea of the verb and denotes an inclusion of other modes of execution if necessary. ');"><sup>24</sup></span> Then let us draw an inference from it.<span class="x" onmousemove="('comment',' That just as there, where he should be decapitated, he is nevertheless executed by any means possible, so here too, where he should be hurled down by the hands of the witnesses, he is still to be executed even if their hands have been cut off. ');"><sup>25</sup></span>