Exodus 2:11-25 -- Moses flees Egypt

Exodus 2:11 Years later, after Moses had grown up, he went out to his own people and observed their forced labor. He saw an Egyptian beating a Hebrew, one of his people. 12 Looking all around and seeing no one, he struck the Egyptian dead and hid him in the sand.

Moses became angry when he saw how his people were being treated.  He killed the Egyptian and hid his body.  

Exodus 2:13 The next day he went out and saw two Hebrews fighting. He asked the one in the wrong, “Why are you attacking your neighbor?”
14 “Who made you a leader and judge over us?” the man replied. “Are you planning to kill me as you killed the Egyptian?”
Then Moses became afraid and thought: What I did is certainly known. 15 When Pharaoh heard about this, he tried to kill Moses. But Moses fled from Pharaoh and went to live in the land of Midian, and sat down by a well.

Even though Moses thought no one had seen the sin he committed, they had.  Pharaoh eventually heard about it and  tried to have Moses killed, but Moses fled.

Exodus 2:16 Now the priest of Midian had seven daughters. They came to draw water and filled the troughs to water their father’s flock. 17 Then some shepherds arrived and drove them away, but Moses came to their rescue and watered their flock. 18 When they returned to their father Reuel he asked, “Why have you come back so quickly today?”
19 They answered, “An Egyptian rescued us from the shepherds. He even drew water for us and watered the flock.”
20 “So where is he?” he asked his daughters. “Why then did you leave the man behind? Invite him to eat dinner.”
21 Moses agreed to stay with the man, and he gave his daughter Zipporah to Moses in marriage. 22 She gave birth to a son whom he named Gershom, for he said, “I have been a foreigner in a foreign land.”

Moses was rewarded for being kind to this family by marrying a daughter of the man he helped and by having a son.

Exodus 2:23 After a long time, the king of Egypt died. The Israelites groaned because of their difficult labor, and they cried out; and their cry for help ascended to God because of the difficult labor. 24 So God heard their groaning, and He remembered His covenant with Abraham, Isaac, and Jacob. 25 God saw the Israelites, and He took notice.

God heard the prayers of his people.  God always hears the prayers of those who are his.  God always answers the prayers of his people.  He may say "no" or "not yet," but he always answers.  We may not know the answer for quite a while.  We may think God is not listening because we do not know the answer, but he always answers.

The verse points out that he "remembered" the covenant with Abraham and Isaac and Jacob.  Does that mean God forgot and that is why the Israelites suffered?  No.  God did not forget about His people, it is us who forget God.  When everything is going well, we tend to forget to thank God or give him praise for the good times, but when things turn bad, we are quick to cry "help!"  We know we need God when times are rough, but we forget we also need him when  things seem good.