Exodus 4:8 & 9

"Then the Lord said, 'If they do not believe you or pay attention to the first miraculous sign, they may believe the second. But if they do not believe these two signs or listen to you, take some water from the Nile and pour it on the dry ground. The water you take from the river will become blood on the ground.'" NIV translation

Throughout the Bible, the number two is associated with witnesses as that was the number required to prove that something was true. God gave Moses two signs and then went above and beyond the law by giving him a third. The third sign was turning water into blood and the number three is associated with the earthly display of God's will. 

Exodus 4:10 - 12

"Moses said to the Lord, 'O Lord, I have never been eloquent, neither in the past nor since you have spoken to your servant. I am slow of speech and tongue.' The Lord said to him, 'Who gave man his mouth? Who makes him deaf or mute? Who gives him sight or makes him blind? Is it not I, the Lord? Now go; I will help you to speak and will teach you what to say.'" NIV translation

Now, Moses doubts his own ability to communicate the words of God to the people. Once again, God meets Moses' doubt with the assurance of His provision. God reminds him that He is the one that made people and that He is in control. God is the same today as in the days of Moses. Do we, as Christians, take our doubts and insecurities about ourselves to the Lord? If we do, we can be comforted with the fact that He is in control and through Him we can do what He asks of us.

Exodus 4:13 - 17

"But Moses said, 'O Lord, please send someone else to do it.' Then the Lord's anger burned against Moses and he said, 'What about your brother, Aaron the Levite? I know he can speak well. He is already on his way to meet you, and his heart will be glad when he sees you. You shall speak to him and put words in his mouth; I will help both of you speak and will teach you what to do. He will speak to the people for you, and it will be as if he were your mouth and as if you were God to him. But take this staff in your hand so you can perform miraculous signs with it.'" NIV translation

Even after God's assurance that He would provide a way for Moses to speak, Moses asks Him to send someone else. So, God has already prepared Aaron and he was on the way to meet Moses. We see that Aaron was to be his mouthpiece and Moses was to be like God to him. What we see here is a pattern that continues even today. God provides a way for men that only requires their acceptance of the fact that He will do something and yet man rejects that in favor of the works of men. That has been described as legalism and has been a tactic used by the devil to undermine the church and the fact that we are saved by grace. We must remember that fear and doubt are not of God and to "be blessed" is to be worry free.