In Genesis 4, the story of Cain and Abel is recounted. The two brothers offered up sacrifices to God. God accepted Abel's but rejects Cain's. Cain became angry that God didn't accept his and jealous that Abel's was accepted. God warned Cain, "If you do well, will you not be accepted? And if you do not do well, sin is crouching at the door. Its desire is for you, but you must rule over it.” (ESV)
Cain was in a tight spot. He failed to please God and was angry that he didn't. Specifically he was angry that his brother did well. As a result, Cain murdered his brother.
Many young men are in Cain's position. We are just starting out in life, taking the first steps outside of college and working on our own. A bunch of us have offered poor offerings to God while in college. We've given him our video games, sports, movies, foolish relationships and worst of all sin as ways of glorifying Him. God has no regard for these things.
Now, we're at point where we can get mad at God for not accepting our works. As a result we can reject the church, shirk our holy responsibilities and walk deeper into sin. The deeper a young man walks in sin, the closer he gets to murdering his fellow brothers and sisters in Christ. In the least, he greatly hurts them.
God warned Cain that sin was crouching at his door. Likewise, sin is crouching at our door. Our lives are unacceptable to God. Sin wants us to take its path.
The question before young men today is whether we will rule over sin or will we be like Cain?