Moses asks how people will recognize that God has sent him. God answers with two practical demonstrations. God turns Moses’ stick into a snake and back again into a stick. God also gives Moses’ hand a bad case of leprosy, then heals it instantly. God calls these “signs” by which the Israelites will believe that God has sent Moses (Exodus 4:1-8).
When Moses performs his first signs, the Egyptians used secret arts to duplicate them (Exodus 7:11, 22; 8:7). Their limited success, however, only emphasized God’s power in two ways: They might start a plague, but only God can end it (Exodus 8:7-8). And each new and more severe plague from God proves that His power is far greater. God declared,
I will send all my plagues on you… so that you may know that there is none like Me in all the earth…. For this purpose I have raised you up, to show you My power, so that My name may be proclaimed in all the earth (Exodus 9:14,16).