While Moses brings up some legit points about people not believing him and such, it also feels to me in a way that he was trying to find a way no to do it. I mean God is like this is what I want you to do and I will be with you making it happen. Moses is all they won't believe me and I don't talk good. We have to believe that if God has called us to do something He will equip us to do it! It's easy to get in the flesh and make excuses not to do what God has told you but doing things through faith that He asks you to is so much more rewarding.
Running away when the staff turned into a snake is a natural response. God tested Moses's faith though by having him grab it by the tail. If you ever dealt with snakes you know you want to get control over the head so it can't bite you.
It irritated God a little bit that Moses didn't have the faith to trust God completely to equip him to do what he was called to do, but He meet him where he was. Allowing Moses's brother Aaron to speak for him.
Verses 24-26 had me confused for a moment cause they seemed out of place. Reading the study notes it made more sense. While God was remembering the covenant and fulfilling it, His people had to remember and follow the conditions of it also. One condition was that the sons needed to be circumcised. Moses's son was not so the Lord was going to have to kill him. Moses's wife I believe being lead by God, preformed a circumcision on him. The reason I believe she was lead by God is I don't think he wanted to really kill the boy but He had to keep His word and follow the covenant. I believe God doesn't want any to parish which is why He give us multiple chances for us to follow Him. Also that's why He meets you were you are and forgives all, so there are no excuses of why you can't be saved.
Chapter 4 ends with the Israelites worshiping God because they believed He would save them. They weren't out of the situation yet, but worshipped anyways. We need to worship God in the middle of our circumstances knowing that He is a faithful God that will get us through anything that comes against us.