(As an extension of this group of posts.)
According to the chronologies that we have, with their precision and imprecision, we can establish the following:
- Yitzchak's Tefillah to Hashem for children (and Rivkah's subsequent revelation) was when Yitzchak was between 59 and 60 years old. (Breishit 25)
- Yaakov's encounter at Beit El, when he was 63 years old. (Breishit 28)
- Avraham was told to move to Eretz Yisrael, some say that this command was given before he left Ur Kasdim, others say that it was when he was in Charan.
- Hashem's promise to Yitzchak on his way to Gerar, when he was at least 75 years old. (Breishit 26, if the prior parshah with mechirat habechorah was was Yitzchak was 75, when Avraham passed away, then this, by smichut haparshiot, is afterwards)