Here we see that Moses, as gifted and educated as he was, was unable to rescue God's people in his own strength. He needed years of discipline and training by God in the obscurity of the Midianite wilderness before he was humble enough to truly be used for God's glory.
Alec Motyer writes, "Even a cursory glance reveals that this passage is a story of failure and of a chronic loss of self-belief. It is all the more striking when we see it against the background of what we learn about Moses himself. He had so much 'going for him.'"