Exodus 4:9

And Moses told Aaron all the words of Yahweh with which He had sent him, and all the signs that He had commanded him to do.

and Aaron spoke all the words which Yahweh had spoken to Moses. He then did the signs in the sight of the people.

So the people believed; and they heard that Yahweh cared about the sons of Israel and that He had seen their affliction. So they bowed low and worshiped.

‘Thus says Yahweh, “By this you shall know that I am Yahweh: behold, I am about to strike the water that is in the Nile with the staff that is in my hand, and it will be turned to blood.