On a peshat level, either
- he did not receive a name until that point, perhaps because they were not certain he would survive, or
- he did receive a name, but for some unspecified reason, the Torah never mentioned it.
At the same time, in Divrei Hayamim 4:18, we read:
and his wife Hajehudijah bore Jered the father of Gedor, and Heber the father of Soco, and Jekuthiel the father of Zanoah--and these are the sons of Bithiah the daughter of Pharaoh whom Mered took.
And Chazal have a general approach that Divrei Hayamim was only given to derash. Therefore, from this pasuk, they darshened many names of Moshe, and gave meanings to these names. Since the end of the pasuk says that these are the sons of Bityah bat Pharaoh, they equate Mered with Calev and Bityah as Bat Par'oh, and make each of the names in this pasuk a separate name of the same individual, Moshe. Thus,
- Avigdor (the father of Gedor)
See Sanhedrin 19b:
R. Johanan says it is derived from the following: And his wife Ha-Jehudiah29 bore Yered the father of Gedor [and Heber the father of Soco, and Jekuthiel the father of Zanoah]30 and these are the sons of Bithia the daughter of Pharaoh, whom Mered took.31 Now, 'Mered' was Caleb; and why was he called Mered?32 — Because he opposed the counsel of the other spies.33 But was he [Moses]34 indeed born of Bithia and not rather of Jochebed? — But Jochebed bore and Bithia reared him;35 therefore he was called after her.
Or Megillah 13a:
R. Simon b. Pazzi once introduced an exposition of the Book of Chronicles as follows: ‘All thy
words are one,
and we know how to find their inner meaning’. [It is written], And his wife the
Jewess bore Jered the father of Gedor, and Heber the father of Socho, and Jekuthiel the father of
Zanoah, and these are the sons of Bithya the daughter of Pharaoh, whom Mered took.
Why was she
[the daughter of Pharaoh] called a Jewess? Because she repudiated idolatry, as it is written, And the
daughter of Pharaoh went down to bathe in the river,
and R. Johanan, [commenting on this,] said
that she went down to cleanse herself
from the idols of her father's house. ‘Bore’: But she only
brought him [Moses] up? — This tells us that if anyone brings up an orphan boy or girl in his house,
the Scripture accounts it as if he had begotten him. ‘Jered’: this is Moses. Why was he called Jered?
Because manna came down [yarad] for Israel in his days.
‘Gedor": [he was so called] because he
fenced in [gadar] the breaches of Israel. ‘Heber’, because he joined [hiber] Israel to their Father in
heaven. ‘Socho’, because he was like a sheltering booth [sukkah] for Israel. ‘Jekuthiel’, because
Israel trusted in God [kiwu le'el] in his days. ‘Zanoah’, because he made Israel abandon [hizniah]
their inquities. ‘Father of’, ‘father of’, ‘father of’: he was a father in Torah, a father in wisdom, a
father in prophecy. ‘These are the sons of Bithya whom Mered took’. Was Mered his name? Was not
Caleb his name?
— The Holy One, blessed be He, said: Let Caleb who rebelled [marad] against the
plan of the spies come and take the daughter of Pharaoh who rebelled against the idols of her father's
There is also the derasha in Sotah 12a:
And when she saw him that he was good.29 It has been taught: R. Meir says: His name was Tob [good]; R. Judah says: His name was Tobiah; R. Nehemiah says: [She foresaw that he would be] worthy of the prophetic gift; others say: He was born circumcised; and the Sages declare, At the time when Moses was born, the whole house was filled with light — it is written here, And when she saw him that he was good, and elsewhere it is written: And God saw the light that it was good.32
The question is what we are to make of such derashos. We could say that Chazal intended these either
1. literally, or
2. homiletically / allegorically ('derech derash', as some Rishonim call it), or
And then, if we say that they meant it literally, then we can either
- agree with them that this is historical truth, as we must
- disagree with them, and thus be heretics, or
- disagree with them, and be Jews in good standing (following e.g. Shmuel HaNagid in Mavo LaTalmud)
My own sense is that, despite these midrashim which give names (corresponding to attributes of Moshe), thus filling in the gaps, none of these names was historically Moshe's name.