TT #49 · Parashas Vayeira · Passuk 19:1
And the two angels came to Sedom in the evening, and Lot was sitting in the gate of Sedom; and Lot saw and rose to meet them, and he bowed down with his face to the ground.
Torah Temimah points to Bava Metzia 86b. E-Daf · Sefaria — Bava Metzia 86b
TT lemma: ויבאו שני המלאכים.
“And the two angels came.” Yet later it is written “And He overturned the cities.” How is this? Gabriel went to overturn Sedom, and Michael went with him to save Lot.
Derash on the verse (Bavli sugya) — not a formal named middah of the 13. The change in number is resolved by assigning distinct roles to each angel.
Only two angels entered Sedom: Gabriel to destroy the city and Michael to rescue Lot; one angel is not given two missions.