The Gemara cites a related story:
The Sages taught:
There was once an incident involving Aḥer,
who was riding on a horse on Shabbat,
and Rabbi Meir was walking behind him to learn Torah from him.
After a while,
Aḥer said to him:
Meir, turn back, for I have already estimated and measured according to the steps of my horse that the Shabbat boundary ends here,
and you may therefore venture no further.
Rabbi Meir said to him:
You, too, return to the correct path.
He said to him:
But have I not already told you
that I have already heard behind the dividing curtain:
“Return, rebellious children,”
apart from Aḥer?
