Reference for Bava Metzia 172:19
כיון דחזא דקא אסר ושרי אמר לאו אורח ארעא למיקם הכא היינו דכתיב (בראשית יח, ב) וישא עיניו וירא והנה שלשה אנשים נצבים עליו וירא וירץ לקראתם מעיקרא אתו קמו עליה כי חזיוהו דהוה ליה צערא אמרו לאו אורח ארעא למיקם הכא
But on seeing him tying and untying [the bandages of his circumcision], He said, 'It is not well that I stand here'; hence it is written, <i>And he lifted up his eyes and looked, and lo, three men stood by him, and when he saw them, he ran to meet them</i>:<span class="x" onmousemove="('comment',' Ibid. 2. ');"><sup>34</sup></span> at first they came and stood over him, but when they saw him in pain, they said, 'It is not seemly to stand here.'<span class="x" onmousemove="('comment',' So they removed to a distance; hence it is first said that they 'stood by him', and then that 'he ran to meet them'. ');"><sup>35</sup></span>