Exodus 4:4-6

American Standard Version

⁴ And Jehovah said unto Moses, Put forth thy hand, and take it by the tail (and he put forth his hand, and laid hold of it, and it became a rod in his hand); ⁵ that they may believe that Jehovah, the God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath appeared unto thee. ⁶ And Jehovah said furthermore unto him, Put now thy hand into thy bosom. And he put his hand into his bosom: and when he took it out, behold, his hand was leprous, as white as snow.