English: “After that” — after he had purchased the field he buried [her], to teach that he did not bury until he had acquired it by a complete acquisition.
On the daf / in context: The sequence “after that he buried” is taken to stress that the burial followed a completed, public purchase; Avraham would not inter Sarah until the title was clear.
Type of Learning
Derash on the verse (midrashic sequence) — not a formal named middah of the 13: the order of the narrative is read as a legal and moral requirement of clear title before burial.
What Is Learned
Avraham buried Sarah only after the field had been fully acquired; the phrase “after that” teaches that the burial waited upon a completed purchase.