Bridegroom of Love by the circumcising (Shemot 4:26)
I am uncircumcised of lips? (Vaera 6:12)
And I live among a people of unclean lips (Isaiah 5.)
"This upward displacement of a genital image ... "
Robert Alter, The Hebrew Bible - A Translation with Commentary
[MS: A Metaphor? This Biblical literary device can take some explaining. Alter unspools the circumcision metaphor in his Notes. As the old joke goes: "What's a meadow for anyway? A Cow?"]
Alter's Translations and Notes
(Copyrighted material: excerpts, formatting and emphasis added)
Verses Vaera 6:10-13
10 And the LORD spoke to Moses, saying,
11 “Come, speak to Pharaoh king of Egypt, that he send off the Israelites from his land.”
12 And Moses spoke before the LORD , saying, “Look, the Israelites did not heed me, and how will Pharaoh heed me, and I am uncircumcised of lips?”
13 And the LORD spoke to Moses and to Aaron and He charged them regarding the Israelites and regarding Pharaoh king of Egypt to bring out the Israelites from the land of Egypt.
....
Verses 6:29-30
29 that the LORD spoke to Moses, saying, “ I am the LORD . Speak to Pharaoh king of Egypt all that I speak to you.”
30 And Moses said before the LORD, “ Look, I am uncircumcised of lips, and how will Pharaoh heed me?”
Alter's Notes
Verse 12 . And Moses spoke before the LORD....
I am uncircumcised of lips? [MS: Note 12 Continued:] The phrase is an approximate parallel ... of the “heavy-mouthed and heavy-tongued” we encountered in chapter 4 .
It is a mistake, however, to represent this upward displacement of a genital image simply as “impeded of speech” because the metaphor of lack of circumcision suggests not merely incapacity of speech but a kind of ritual lack of fitness for the sacred task (like Isaiah’s “impure lips” in his dedication scene, Isaiah 6).
[MS:Isaiah (5-6) I cried, “Woe is me; I am lost! For I am a man of unclean lips And I live among a people Of unclean lips; Yet my own eyes have beheld The King LORD of Hosts.” ]
The idiom is clearly intended to resonate with the Bridegroom of Blood story, in which Moses is not permitted to launch on his mission until an act of circumcision is performed.
Syntactically, this last clause of the verse dangles ambiguously: Moses’s thought was already complete in the a fortiori relation between the first and second clauses (if the Israelites wouldn’t listen to me, how much more so Pharaoh . . .), and now Moses offers a kind of reinforcing afterthought—and anyway, I am uncircumcised of lips.
Verse 30. Look, I am uncircumcised of lips, and how will Pharaoh heed me?
This sentence repeats verbatim Moses’s demurral in verse 12, reversing the order of the two clauses and omitting the first clause about Israel’s failure to heed Moses.
The recurrent language is a clear-cut instance of a compositional technique that biblical scholars call “resumptive repetition”: when a narrative is interrupted by a unit of disparate material—like the genealogical list here—the point at which the story resumes is marked by the repetition of phrases or clauses from the point where the story was interrupted. [MS: "Resumptive repetition" is explained in Alter's essay-Introduction to Exodus, see the link MS Sefaria sheet.]
Moses’s report of Israelite resistance to his message is not repeated because the focus now is on the impending confrontation between him and Pharaoh.
For the same reason, “how will Pharaoh heed me?” is repositioned at the end of Moses’s speech because it will be directly followed by God’s enjoining Moses and Aaron to execute the first portent intended to compel Pharaoh’s attention.
Alter, Robert. The Hebrew Bible: A Translation with Commentary (pp. 645-647, 650).