Moses declined God’s assignment to go to Pharaoh and demand that he let the Israelites go. He insisted that he was not qualified since he had a speech impediment.
“And Hashem said to him: Who has made man’s mouth or makes him mute or deaf or sighted or blind? Is it not I, Hashem?” (Exodus 4:11)
The Baal Shem Tov asked why does the Torah list the clear-sighted person among those who are impaired? He answered that it is to remind every whole and healthy person that s/he too has blemishes, faults and imperfections.