Exodus 4:1 says, And Moses answered and said, But, behold, they will not believe me, nor hearken unto my voice: for they will say, The LORD hath not appeared unto thee.  Moses began making excuses why he could't do what God called him to do.  If God calls us to do something, we do not need to look for excuses why we cannot do it.  Moses said that the people would not believe him when he told them that God had appeared to him.  Many people today will not believe us as followers of Christ when we tell them that God has appeared to us, but if we are His followers, God has to have appeared to us.  This may not have been a physical appearance, but we cannot follow Christ if we have not met Him in a personal encounter.  No one can really disprove this relationship.  Verse two states, And the LORD said unto him, What is that in thine hand? And he said, A rod. God asked Moses what he was holding and Moses said a rod.  This was nothing unusual.  God can and does work through everyday things and events to reveal Himself to people.  Verse three adds, And he said, Cast it on the ground. And he cast it on the ground, and it became a serpent; and Moses fled from before it.  When Moses did what God commanded and threw the rod on the ground, it became a serpent and Moses fled from it.  Though we do not have rod's that become serpents when we are witnessing to others, we have the power of the Holy Spirit with us, and that is even greater.  Verse four declares, And the LORD said unto Moses, Put forth thine hand, and take it by the tail. And he put forth his hand, and caught it, and it became a rod in his hand:  God told Moses to take the serpent by the tail, and when he did, it became a rod again.  It took faith on Moses' part to do this, just as it will take faith on our part to do what God calls us to do today.  Verse five adds, That they may believe that the LORD God of their fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath appeared unto thee.  God was about to provide Moses with another sign that He had sent Moses.  God also once again identified Himself as the God of Abraham, Isaac, and Jacob.  He is the same God, the only God there is, that we worship today as followers of Christ.  We cannot claim that there may be other gods.  Verse six says, And the LORD said furthermore unto him, Put now thine hand into thy bosom. And he put his hand into his bosom: and when he took it out, behold, his hand was leprous as snow.  When Moses put his hand under his coat and pulled it out, it was as white as a leprous hand.  Again, this may not have been a sign that Moses was looking for, but it would get people's attention.  We must rely on God to get people's attention when we witness to them today.  Though God may not give us physical signs, He is still God and will give us the ability to witness effectively.  Verse seven adds, And he said, Put thine hand into thy bosom again. And he put his hand into his bosom again; and plucked it out of his bosom, and, behold, it was turned again as his other flesh.  The sign was not just the hand becoming leprous, but the restoration of the hand to a healthy condition as well.  When God does give a sign, there can be no doubt that it is His work.  Verse eight states, 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.  God said if the people would not believe the first sign that that they would believe the voice of the second sign.  God was the Voice behind both signs.  Though we don't go with signs, if we are witnessing for God today, it is His voice that is behind our witness.  Verse nine concludes, And it shall come to pass, if they will not believe also these two signs, neither hearken unto thy voice, that thou shalt take of the water of the river, and pour it upon the dry land: and the water which thou takest out of the river shall become blood upon the dry land.  God then offered a third sign for those who would not believe the first two.  God will always offer ample proof of His existence to those that we witness to.