Those who know little of Christianity assume that 'sin' is the committing of 'wrong deeds' - and that is only a partial truth. Attempting to get the point across is not easy and so this is how I explain it to schoolchildren.
Take three people who all share a similar thought:
a] Humphrey has it come into his mind the idea to hit Bertie with a baseball bat. Stops, thinks and rejects the idea as wrong.
b] Marlon has the same thought and strikes Bertie with the aforementioned piece of sporting equipment.
c] Percy shares the thought and rejects it because, although he really likes the idea, he is afraid of the consequences.
In these three we have something of an overview of Man.
Humphrey resists temptation. He cannot be blamed for the thought as he has rejected it.
Marlon has committed the sin and is clearly wrong.
Percy though, is an interesting case. From a God's eye view, he is just as bad as Marlon. He has embraced the sin; likes the sin; holds onto it and this makes him rotten inside. The only reason he has not committed the act is fear.
From Bertie's point of view, clearly the Percy outcome is better than the Marlon one - but not so with God, who sees us within and sees the real person not just the outward one.
