The Torah asserts that Miriam was a prophet (Exodus 15:20); and Numbers 12:2 quotes Miriam and Aaron saying, “Has the Lord spoken only through Moses? Has He not spoken through us as well?” We should take these statements seriously; they are very unlikely to be latter additions because female religious leaders become very rare in post-Biblical times.
Further, the Talmud (Megillah 14a) lists Miriam as one of seven major female prophetesses of Israel, and also states that she was so righteous that due to her merit, the Israelites drank water from her well for forty years in the Wilderness (Taanit 9a). So when and what did God speak through Miriam? What was Miriam’s Torah (teaching)?
Exodus 15:20 is the only place in all of scripture where Miriam is described directly as a prophetess. The Kli Yakar commentary to this verse states that Miriam prophesied at this point, during the “Song of the Sea”. The Torah describes how Miriam called out to the women to sing; using the masculine “lahem” in place of the feminine “lahen”. Why?
The Kli Yakar commentary explains that women have often been ignored, oppressed, disadvantaged, and generally treated as second-class citizens compared to men (an amazing admission for a rabbi who lived between 1550-1619 CE).
What Miriam prophesied is that a time would come when women would be equal to men in all ways, hence the use of the masculine lahem. Also, since the song itself is grammatically in the first person, it could just as easily been first sung by Miriam and later ascribed to Moses. Or perhaps since Moses had a speech problem Miriam; sang the words in honor of the efforts of Moses.
Freeing ourselves from the gender assumptions of the past, we could also say Miriam wrote down the narrative oral Torah from Genesis 12 through Genesis 50 which Israel must have known, while Moses was in Midian. Midrash Exodus Rabbah 5:18 and Tanhumah Va’era 6 both state that the Israelite slaves in Egypt “possessed scrolls which they read”.
This probably refers to the oral narrative Torah that Miriam the prophet wrote down for them.
Miriam also could have written the first 15 chapters of Exodus from “these are the names” to the song she and all the Jewish woman sang when Israel safely crossed the Sea of Reeds. As the Torah states, “Miriam the prophet, Aaron’s sister, took a tambourine in her hand, and with all the women following her, dancing with tambourines; Miriam sang this refrain: Sing to the Lord…” (Exodus 15:21).
Miriam could also have written the Marah narrative where “the Lord placed statute and ordinance” on the Jewish people to get them ready for the covenant at Sinai. What do “statue and ordinance” refer to? The Mechilta records two opinions: “statute” – refers to Shabbat, “ordinance” – refers to honoring parents, this is the opinion of Rabbi Yehoshua.
Rabbi Eliezer Hamodai says: “statute” – refers to sexual prohibitions, as it says (Vayikra 18:30): “that you not commit any of these abominable customs (“chukot”)”, “ordinances” – this refers to laws about robbery, laws about fines, and laws about injuries/damages.
Both of these Sages are referring to the same set of laws: Leviticus 18:26 which begins “You shall observe my statutes and my ordinances” and ends 19:37 with “You shall observe my statutes and my ordinances”. This section does include the Mitsvot to observe the Sabbath (19:3&30) and to revere your parents (19:3) as Rabbi Joshua states.
It also includes Mitsvot relating to honest business practices, (19:13&36), robbery (19:13), and prostitution (19:29) as Rabbi Eliezer Hamodai states.
This section, sometimes called the holiness code, also includes the Mitsvot to love your neighbor as yourself (19:18) and the Mitsvah to love the stranger as yourself because you were strangers in the land of Egypt (19:34). We could say this section (Leviticus 18:26-19:37) was given to Miriam and Moses at Marah and then written down as a special memorial book (Exodus 17:14).
It was originally part of the Book of the Covenant-Exodus 20:1-24:7 and only later moved and inserted as part of the priest’s rulebook. Others could say this section was given to Miriam as oral law Torah and was included in the covenant at Sinai but was not written down until later.
In a few generations, as the Jewish People become used to Female Rabbis, these ideas will seem more reasonable.