Now, for another illustration, look at this train diagram to help explain some key Christian concepts and terminology:
Everyone comes into the world on Track 1, headed for hell (original sin) because of sin, and stays on Track 1 unless the person makes a deliberate decision to get off and go to Track 2.
Because God is just, there are exceptions, as explained in Jesus only way?: for children ... for mentally handicapped ... for people who have never clearly heard about Jesus ...
But the exceptions don't apply here. We KNOW, or at least are put on notice to investigate further. Now we will be held accountable, individually, for our response.
For everyday shortcomings, we usually use a softer term for evil. We call it Sin.
Generally, we know what sin is, from our conscience, from the Bible and from our civil laws.
The key point is not that we must eliminate all sin from our lives – we can't because we're human – or that we must identify and atone for every sin.
The key point is that every person, humbly and individually, must acknowledge that he or she is a sinner and needs Jesus Christ as Savior. This is the core Christian belief, as explained by God's character.