Then Moses answered, "What if they won't believe me and will not obey me but say, 'The Lord did not appear to you'?"
References for Exodus 4:1
The Lord asked him, "What is that in your hand?" "A staff," he replied.
Then He said, "Throw it on the ground." He threw it on the ground, and it became a snake. Moses ran from it,
but the Lord told him, "Stretch out your hand and grab it by the tail." So he stretched out his hand and caught it, and it became a staff in his hand.
"This will take place," He continued, "so they will 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."
In addition the Lord said to him, "Put your hand inside your cloak." So he put his hand inside his cloak, and when he took it out, his hand was diseased, like snow.
References for Exodus 4:6