Parashas Eikev · Passuk 11:21
to the end that you and your children may endure, in the land that GOD swore to your fathersifathers See note at 1.35. to assign to them, as long as there is a heaven over the earth.
Torah Temimah points to Sanhedrin. (שם שם — same source as the previous unit).
TT lemma: כימי השמים וגו' (unit 8 of 9).
English: Rabbi Yehudah said in the name of Shmuel: The days of Mashiach are as from the day the world was created until now, as it is said, “like the days of the heavens over the earth.”
Derash on the verse (Bavli sugya) — not a formal named middah of the 13
The Gemara uses this passuk in a sugya (proof, illustration, or dispute). Named as one of R' Yishmael’s 13 or R' Eliezer’s 32 only when that move is explicit.
The phrase “like the days of the heavens over the earth” is taken as a measure of the Messianic span.