"The next day he went out and saw two Hebrews fighting. He asked the one in the wrong, 'Why are you hitting your fellow Hebrew?' The man said, 'Who made you ruler and judge over us? Are you thinking of killing me as you killed the Egyptian?' Then Moses was afraid and thought, 'What I did must have become known.' When Pharaoh heard of this, he tried to kill Moses, but Moses fled from Pharaoh and went to live in Midian, where he sat down by a well." NIV translation
The next day, Moses tried to do the right thing and break up a fight between two of his fellow Hebrews. In doing so, he found out that the murder that he committed was not a secret and, in fact, Pharaoh found out and tried to kill him. This is a reminder to us that, even though we may think that our sins are hidden, they are known. It also reminds us that Moses was not chosen to deliver the people based on his own goodness as he was known to be a murderer. In the same way, we as Christians are not chosen to serve God based on our goodness but on the goodness of God.