Cain and Abel Syndrome

The kids are on the trampoline, "play fighting." I am not sure how much of it is play vs just getting frustrations out on the other sibling. They were very quarrelsome right before lunch, and I warned them if there were any more cross words at each other, they would BOTH be grounded from TV and computer. I think they decided to duke it out on the trampoline. Which would be fine, except there is a huge age difference. Travis is 14, Morgan only 7. For those of you who know us well, your probably placing your bets on Morgan to be the winner. She is that aggressive, and if you know Travis, he would never really hurt his sister intentionally.
Have any siblings ever NOT fought? Have any of you ever not either hit or been hit by one of your siblings (assuming you have one?) Today part of our lesson in Church was on Cain and Abel. If you have never heard of this story then you probably didn't grow up in the Northern Hemisphere. Cain "slew" Abel. The first murder. Jealousy. Aren't we all jealous though in some way? Even small things like "I wish I had a pool" could be some sort of jealousy, right? Are we ever really satisfied with the gifts God has given us, or are we always wanting more? Maybe that is a question we should ask ourselves everyday. It's OK to want a pool. Just don't hate your neighbor because he has one. And maybe don't let your resentment of not having a pool cloud your relationship with God. My analysis probably is not theologically correct, but it is worth thinking about. By the way, I have been thinking about a pool a lot lately, but a) our yard is probably too small and b) John wouldn't pay for it.
Meanwhile, the play fighting is over. Morgan came into the house crying because Travis "hit her in the eye." Actually, it is the side of her eye. She recovered quickly. So if you see her and she has a black eye, you know why. Also, you may have lost money on a bet, but there's always next time.