Exodus 6:12

How then shall Pharaoh hear me? — This time the objection comes from Moses. His double rejection, by Pharaoh (Exodus 5:1) and by Israel (Exodus 6:9), had thrown him back into utter despondency. All that diffidence and distrust of himself which he had shown in his earlier communications with Jehovah (Exodus 3:11; Exodus 4:1; Exodus 4:10; Exodus 4:13) revived, and he despaired of success in his mission. Was it of any use his making a second appeal to the foreign monarch when he had failed with his own countrymen?

Uncircumcised lips. — Rosenmüller argues from this expression that Moses was “tongue-tied;” but it is not clear that more is meant here than in Exodus 4:10, where Moses says that Hebrews 13 “slow of speech and of a slow tongue.” He had some difficulty of utterance; but whether or not it was a physical impediment remains uncertain. “Uncircumcised” is used, according to the Hebrew idiom, for any imperfection which interferes with efficiency. An “uncircumcised ear,” is explained in Jeremiah 6 to be an ear that “cannot hearken;” and an “uncircumcised heart: (Lev. xxvi 41) is a heart that fails to understand.