Rashi(one of the prominent Bible commentators) says that it means - is
there anyone other than Moshe Rabbeinu (Moses) who has ascended to heaven
and returned.? Is there anyone who has accomplished what he did and
established halacha (the law)? If there was - "What is his name"?, who
was he? - we would surely know who he was and his background. "What is his
son's name"? - what family has descended from him and what records do we
have of him? - meaning, if somehow you have forgotten this "navi"'s
(prophet's) name, at least you would know the names of his children and
other descendants. Metzudas David states that since there was no such
person, we do not have the right to go against the Torah merely on the
basis of philosophical speculation.
I think that this is actually stating that just because there is a myth
about a person called y'shu (Jesus) we should not allow ourselves to be
pulled away from the Torah. Anyone who makes claims about halacha (law)
must be able to point to the source. For example, we know who the Rambam,
Rashi, Rav Moshe Feinstein, or the Lubavitche Rebbe were and what they wrote.
Hillel (Sabba) Markowitz
H.E.Markowitz@hrb.com