Exodus 5 & 6 – Moses reverts back to his old excuses. He, too, has lost heart. 2017

Exo 6:9
So Moses spoke thus to the sons of Israel, but they did not listen to Moses on account of their despondency and cruel bondage.

So often the tragedies of the immediate circumstances cloud one's ability to hear the True words of comfort and hope. They had lost heart at this time.

Exo 6:10
Now the LORD spoke to Moses, saying,

Exo 6:11
"Go, tell Pharaoh king of Egypt to let the sons of Israel go out of his land."

Exo 6:12
But Moses spoke before the LORD, saying, "Behold, the sons of Israel have not listened to me; how then will Pharaoh listen to me, for I am unskilled in speech?"

Moses reverts back to his old excuses. He, too, has lost heart. This may look as though Moses is saying that he has a speech impediment. But the term translated as "unskilled in speech" should actually be translated as "uncircumcised lips" as most other translations do.