Exodus 4:9

9 And it shall come to pass, if they will not believe also those two signs, neither hearken unto thy voice, that thou shalt take of the water of the river, and pour [it] on the dry [land]; and the water that thou takest out of the river shall become blood upon the dry [land].

Exodus 4:9 In-Context

7 And he said, Put thy hand into thy bosom again. And he put his hand into his bosom again, and took it out of his bosom, and behold, it was turned again as his flesh.
8 And it shall come to pass, if they will not believe thee, neither hearken to the voice of the first sign, that they will believe the voice of the other sign.
9 And it shall come to pass, if they will not believe also those two signs, neither hearken unto thy voice, that thou shalt take of the water of the river, and pour [it] on the dry [land]; and the water that thou takest out of the river shall become blood upon the dry [land].
10 And Moses said to Jehovah, Ah Lord! I am not eloquent, neither heretofore nor since thou hast spoken to thy servant, for I am slow of speech and of a slow tongue.
11 And Jehovah said to him, Who gave man a mouth? or who maketh dumb, or deaf, or seeing, or blind? [have] not I, Jehovah?
The Darby Translation is in the public domain.