TT #9 · Parashas Vayeitzei · Passuk 28:13
And behold Hashem was standing over him and said, “I am Hashem, the God of Avraham your father and the God of Yitzchak; the land on which you are lying I will give to you and to your offspring.”
Torah Temimah points to Yerushalmi Berachos 4:3.
TT lemma: אלהי אברהם.
Sefaria — Yerushalmi Berachos 4:3
English: It was taught: Why do we pray eighteen blessings every day? Rabbi Chanina said in the name of Rabbi Pinchas: Corresponding to the eighteen times that the Avos are written in the Torah — Avraham, Yitzchak and Yaakov.
Derash on the verse (Yerushalmi) — not a formal named middah of the 13. The repeated naming of the Avos supplies the numerical correspondence for the eighteen berachos.
The eighteen blessings of the Amidah correspond to the eighteen times the patriarchs are written in the Torah.