2 Samuel 1-2

Chap.1: David is mourning Saul and Jonathan's death... I don't really understand... Saul tried to kill David many, many times. And Jonathan was a loyal friend. Yet somehow, David is mourning them equally; "Saul and Jonathan- in life they were loved and admired, and in death they were not parted. They were swifter than eagles, they were stronger than lions..."vs.23.
I guess it was because Saul was the "Lord's annointed." I mean yes, that means a lot. I just don't really get it...
And then there is this whole battle between the house of David and the house of Saul. Everything chasing after each other trying to kill each other... Crazy.