Exodus 4:1-5

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

2And the LORD said to him, What is that in thy 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 the LORD said to Moses, Put forth thy 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 the LORD God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath appeared to thee.