Exodus 4:6-9

The LORD furthermore said to him, “Now put your hand into your bosom.” So he put his hand into his bosom, and when he took it out, behold, his hand was leprous like snow. Then He said, “Put your hand into your bosom again.” So he put his hand into his bosom again, and when he took it out of his bosom, behold, it was restored like the rest of his flesh. “If they will not believe you or heed the witness of the first sign, they may believe the witness of the last sign. But if they will not believe even these two signs or heed what you say, then you shall take some water from the Nile and pour it on the dry ground; and the water which you take from the Nile will become blood on the dry ground.”