Exodus 4:2-5

2And Jehovah said to him, What is that in thy hand? And he said, A staff.

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 Jehovah said to Moses, Stretch out thy hand and take it by the tail — and he stretched out his hand and caught it, and it became a staff in his hand —

5that they may believe that Jehovah, the 1God of their fathers, the 2God of Abraham, the 3God of Isaac, and the 4God of Jacob, hath appeared unto thee.