Exodus 4:7-12
English Standard Version
Chapter 4
7Then God said, "Put your hand back inside your cloak." So he put his hand back inside his cloak, and when he took it out, behold, it was restored like the rest of his flesh. 8"If they will not believe you," God said, "or listen to the first sign, they may believe the latter sign. 9If they will not believe even these two signs or listen to your voice, you shall take some water from the Nile and pour it on the dry ground, and the water that you shall take from the Nile will become blood on the dry ground."
10But Moses said to the Lord, "Oh, my Lord, I am not eloquent, either in the past or since you have spoken to your servant, but I am slow of speech and of tongue."
11Then the Lord said to him, "Who has made man 's mouth? Who makes him mute, or deaf, or seeing, or blind? Is it not I, the Lord?
12Now therefore go, and I will be with your mouth and teach you what you shall speak."