English: Until Avraham there was no [visible] old age. Whoever wished to speak with Avraham would [mistakenly] speak with Yitzchak; whoever wished to speak with Yitzchak would speak with Avraham. Avraham came and requested old age, as it is said “And Avraham was old, advanced in days.”
On the daf / in context: The sugya explains that before Avraham people looked alike across generations; Avraham asked for the distinguishing mark of old age so that father and son could be told apart. The same motif appears with regard to Yitzchak’s resemblance to Avraham.
Type of Learning
Custom (Bavli — introduction of visible old age)
What Is Learned
Visible signs of age began with Avraham’s request, so that the generations could be distinguished and proper honor given according to seniority.