Following God will always put us in situations where we are called to do things that are beyond our capabilities. In Moses’ case God called him to speak and act on his behalf in front of Pharoah despite his insecurities and struggles with public speaking. What is critical for us to know is that, although the things God calls us to may be beyond our capabilities, they are never beyond his capabilities. We may not be able, but God is able. (The main thrust of this is found in vs. 1-17)
Cambridge: Exodus