Exodus 4:2-5, 17

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 he threw it on the ground, and it became a serpent; and Moses fled from it. But the LORD said to Moses, “Stretch out your hand and grasp it by its tail”—so he stretched out his hand and caught it, and it became a staff in his hand— “that they may believe that the LORD, the God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, has appeared to you.”

You shall take in your hand this staff, with which you shall perform the signs.”