Parashas Vayeira · Passuk 18:5
And I will take a morsel of bread, and you shall sustain your hearts; afterward you may pass on, since you have come to your servant. And they said, “Do so, as you have spoken.”
Torah Temimah points to Nedarim 37b.
TT lemma: אחר תעברו.
English: “Afterward you may pass on.” Rabbi Yitzchak said: The adornments of the Soferim are a law given to Moshe at Sinai, and “afterward you may pass on” is one of the adornments of the Soferim.
Derash on the verse (Bavli sugya) — not a formal named middah of the 13. The particle is identified as a traditional scribal clarification (ittur soferim).
The word “achar” (“afterward”) in this verse is counted among the traditional “adornments of the Soferim,” a reading clarification transmitted from Sinai.