Reference for Yoma 93:12
ושוב אמרו עליו על רבי ישמעאל בן קמחית פעם אחת יצא וסיפר עם אדון אחד בשוק ונתזה צינורא מפיו על בגדיו ונכנס יוסף (עם) אחיו ושמש תחתיו וראתה אמן שני כהנים גדולים ביום אחד
[to interpret the divergence thus]: David said before the Holy One, blessed be He: Lord of the Universe, Thou hast [first] 'carefully sifted' and then strengthened me. It was told of R'Ishmael B'Kimhith<span class="x" onmousemove="('comment',' Tosaf. Yoma III.');"><sup>19</sup></span> that one day he talked in the street to an Arab, and spittle from his mouth flew on his garments,<span class="x" onmousemove="('comment',' It was on the nay of Atonement, he was to minister as high priest and the spittle defiled and thus prevented him from officiating.');"><sup>20</sup></span>