Exodus 4:1-5

1And Moses answered and said, But, behold, they will not believe me, nor hearken unto my voice: for they will say, Yhwh hath not appeared unto thee.

2And Yhwh said unto him, What is that in thine hand? And he said, A rod.

3And he said, Cast it on the ground. And he cast it on the ground, and it became a serpent; and Moses fled from before it.

4And Yhwh said unto Moses, Put forth thine hand, and take it by the tail. And he put forth his hand, and caught it, and it became a rod in his hand:

5That they may believe that Yhwh God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath appeared unto thee.