Story of the Ba'al Shem

Daf Hashavua
Eruvin 97 a


The Gemoro says, the father of Shmuel the son of Rav Yitzchok , learned
“Detoni Avuha d’Shmuel Bar Rav Yitzchok”
a) The father of Shmuel was the son of Rav.Yizchok (R.Y. grandfather of Shm.)
b) The father of Shmuel was Rav Yitzchok ( R.Y. father of Shm.)
a or b ???
The Seder Hadoros has an entry “ Rav Yitzchok Avuha d’Shmuel” (b)
He also has an entry “ R. Shmuel bar Yitzchok” (b)
Seems B is the correct answer, if so, we need to understand why does the
Gemoro say The Father of R. Shmuel the son of Rav Yitzchok? It would
have been much simpler to say R. Yitzchok or R. Yitzchok the father
of Shmuel.
Tosfos (Kidushin 73a dh Mai Ika) brings a Ba’al Shem *story from the Yerushalmi.
The father of Shmuel was in Medinas Hayom (distant country) He came back
using a shem (magic carpet). to his wife and had relations with her(went back).
And Shmuel was born.
They started calling R. Yitzchok “Avuha d.Shmuel” (Father of Shmuel)
In order to publicize that Shmuel was a legitimate son and R.Y. was the father.
From then on he was called and known as Avuha d’Shmuel
*More than a thousand years before R. Yisroel Besh”t