Parashas Vayechi · Passuk 48:16
The angel who hath redeemed me from all evil, bless the lads; and let my name be named in them, and the name of my fathers Avraham and Yitzchak; and let them grow into a multitude in the midst of the earth.
Torah Temimah points to Yerushalmi Berachos 4:3.
TT lemma: שמי ושם אבותי.
English: It was taught: Why do we pray eighteen blessings every day? R’ Chanina said in the name of R’ Pinchas: Corresponding to the eighteen times the patriarchs are written in the Torah — Avraham, Yitzchak and Yaakov. And if one says to you they are only seventeen — say to him: “And let my name be named in them, and the name of my fathers Avraham and Yitzchak” — count them (including this mention of Yaakov).
Numerical asmachta — the mention of “my name” together with the names of the fathers completes the count of eighteen.
The eighteen blessings of the Amidah correspond to the eighteen times the patriarchs are named in the Torah; this verse supplies the final occurrence that brings the total to eighteen.