This is the second of the three miraculous signs that God gave to Moses to prove his calling. This sign proves that nothing good can come of our flesh(Rom.7:18). One writer puts it this way: ” Selfishness and corruption are found everywhere within our flesh. If you think that is not true, just put your hand inside your flesh and see.” The hand came out leprous, and got healed the same way. These signs were not only to convince Moses, but primarily those who will doubt the call. God gives us signs as mark of protecting the call, but also to announce His name. This sign introduces Jehovah Ropheka, the Lord our healer. Gods announcement through this sign was to be a healing balm to all the sufferings and diseases of the people of Israel. Jesus also came as a healer. Today may the healing balm of this miracle rub off on every struggles we face today. Its just the second miracle.
And it shall come to pass, if they will not believe thee, neither hearken to the voice of the first sign, that they will believe the voice of the latter sign. Exodus 4:8 KJV