Believe it or not, it all starts with man being a sinner.

The word 'sin' means to "miss the mark".  We fall short of God's perfect character.

There are 3 ways that we can sin:
  1. Thinking evil thoughts such as hate, lust, or greed
  2. Speaking evil things such as gossip, lying, or cursing
  3. Doing evil things such as stealing or sexual immorality

Even if we have done more good than bad, God is the standard of perfection.
All have sinned, and fall short of the glory of God.

Romans 3:23
Whoever shall obey the whole law, and yet sins in one point, he is guilty of all.

James 2:10