Reference for Shabbat 304:11
גששיה חזייה דאית ביה מששא אמר ליה ליקום מר לגוויה דביתא אמר ליה גלית אדעתך דאפילו נביאי לא קרית דכתיב (יחזקאל לז, יג) וידעתם כי אני ה' בפתחי את קברותיכם
while one angel stands at one end of the world and a second stands at the other end, and they sling their souls to each other, for it is said, and the souls of thine enemies, them shall he sling out, as from the hollow of a sling. Rabbah asked R. Nahman: What about those who are intermediate? Had I died I could not have told you this, he replied. Thus did Samuel say: Both these and those [the wicked and the intermediate] are delivered to Dumah;<span class="x" onmousemove="('comment',' The guardian angel of the deceased. [The name is probably Silence, which is the meaning of Dumah, personified.] ');"><sup>10</sup></span>