God gave Moses a HUGE assignment. Moses doubted his own ability to fulfill the mission just like we do. Henry Blackaby wrote in his study Experiencing God when we think things like that, we are really saying more about what we believe about God than what we believe about ourselves. God is powerful enough to work through anyone He chooses. That includes you and me.
Moses doubted and asked God what if the Israelites would not even believe God appeared to Moses in the first place. God responded with three signs in Exodus 4:1-13. I am only going to address the first one. Moses' profession for forty years was a shepherd. One of the most important tools for a shepherd was his staff. It could be used to prod sheep along, rescue a fallen sheep from a ledge, or fight off prey attacking the sheep.
God told Moses to throw his staff down on the ground. I find this symbolic. It is like God was saying, "Throw down your identity as a shepherd. Throw down your old way of life. Throw down the familiar and comfortable life you have known for forty years. Throw down living beneath your destiny.
When Moses threw the staff down it turned into a serpent causing Moses to flee. God told Moses to do something very strange. He told Moses to pick up the serpent by the tail. Everybody knows the business end of a snake is the head. Especially venomous ones. Watch snake handlers catch snakes by the head so they cannot be bit. To pick up a venomous snake by the tail is to invite trouble. It defies logic. Does not make sense. Is irrational.
I find God often asks us to do things that don't make sense. He tests our faith repeatedly. He constantly pushes us beyond our comfort zones. He nudes us toward things that look illogical. It comes down to obedience by faith. Will we trust what God says or what our eyes see?
Incredulously Moses stretched out his hand putting himself at risk. When he grabbed the tail it immediately turned back into his staff. I am sure he was greatly relieved. He learned a valuable lesson. God can be trusted. Even when obedience defies logic. That was to be the first of many tests Moses would face leading the Israelites. Small tests build our faith for the larger assignments down the road. We have a choice to obey or give into logic.