Exodus 6:12

ואיך ישמעני פרעה HOW THAN SHALL PHARAOH HEAR ME? — This is one of the ten inferences from minor to major which are found in the Bible (Genesis Rabbah 92:7). ערל שפתים OF UNCIRCUMCISED LIPS — It really means obstructed as regards the lips. So, too, in respect to all forms derived from ערל I say that they signify obstructed. E. g. (Jeremiah 6:10) “their ear is עֲרֵלָה — stopped up so that it will not hear; (Jeremiah 9:25) “עַרְלִי in heart” — their hearts are closed so that they will not understand; (Habakkuk 2:16) “Drink thou, also וְהֵעָרֵל” — and become thou closed up (in thy senses) through intoxication caused by the cup of curse mentioned in that passage; the foreskin (ערלה) of the flesh is so called because the membrum is closed up and covered by it; (Leviticus 19:23) וערלתם ערלתו signifies, make for it (the tree) a closure (אוטם) and cover by means of an inhibition that will prove a barrier against eating it; (Leviticus 19:23 “Three years shall it be to you as ערלים” — it shall be closed up and covered and barred so that it many not be eaten.

וַיְדַבֵּ֣ר מֹשֶׁ֔ה לִפְנֵ֥י יְהֹוָ֖ה לֵאמֹ֑ר הֵ֤ן בְּנֵֽי־יִשְׂרָאֵל֙ לֹֽא־שָׁמְע֣וּ אֵלַ֔י וְאֵיךְ֙ יִשְׁמָעֵ֣נִי פַרְעֹ֔ה וַאֲנִ֖י עֲרַ֥ל שְׂפָתָֽיִם׃ {פ}

And Moshe spoke before the Lord, saying, Behold, the children of Yisra᾽el have not hearkened to me; how then shall Par῾o hear me, who am of uncircumcised lips?