Exodus 4:2-5

And the LORD said to him, “What is that in your hand?” And he said, “A staff.” Then He said, “Throw it on the ground.” So Moses threw it on the ground, and it became a [living] serpent [like the royal symbol on the crown of Pharaoh]; and Moses ran from it. But the LORD said to Moses, “Reach out your hand and grasp it by the tail.” So he reached out his hand and caught it, and it became a staff in his hand— [“You shall do this,” said the LORD,] “so that the elders may believe that the LORD, the God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, has [most certainly] appeared to you.”