Rambam: Shemot: God’s Guiding Hand
The Guide of the Perplexed, Volume II, Chapter 45:The first of the degrees of prophecy consists in the fact that an individual receives a divine help that moves and activates him to a great, righteous, and important action.
Know that such a force did not abandon Moshe, our teacher, from the moment he reached maturity. It was because of this that he was moved to slay the Egyptian and to reprove the one who was in the wrong among the two men that struggled.
The strength of this force shows in the fact that when – after having been filled with fear and having fled – he came to Midian as a stranger full of fear and saw some wrong that was done, he could not refrain from putting an end to it and was incapable of patience with regard to it, as it says, “But Moshe stood up and helped them.” (Exodus 2:17)