In chapter three, Ish-bosheth made a bad mistake. He forgot who really put him in the throne. It was Abner who made it possible for Ish-bosheth, King Saul’s son, to ascend to the throne. It was Abner’s cunning and strength as a leader who put him there. Ish-bosheth was not a leader, and he severely misjudged the consequences of accusing Abner of sleeping with Saul’s concubine.
Abner’s response was basically, “How dare you accuse me of this! I served your father well. I kept you from defeat at David’s hands. I put you in the throne, and now I’m going to take you out of it. I will make sure that David becomes King of all Israel.”
Ish-bosheth was gobsmacked. He couldn’t say a thing. He knew he was powerless against Abner.
And Abner went to David and proposed to ally himself with David, which David agreed to.
When Joab, the general of David’s army heard about the agreement, he was not happy and said as much to David. He rightfully didn’t trust Abner, and thought Abner had come to David as a spy. And he took it upon himself to murder Abner.
David, being an honorable man, mourned for Abner and gave him a proper and honorable funeral.
In chapter four, when Ish-bosheth heard about Abner’s murder, things really begin to fall apart quickly for him. He loses any semblance of control, and two of his military leaders murder him and then make the same mistake made by the man who murdered Saul. These two thought they were doing David (and themselves) a favor by killing one of David’s enemies. They figured they would ingratiate themselves to David by doing this deed, but their fate was the same as Saul’s murderer. David had them killed, and then hung by the pool in Hebron.
There is a difference between killing in war and murder. Many people think that one of the ten commandments says “Thou shalt not kill”, and it does say that in the King James Version. But when you look at the original language, the Hebrew, the word used is better translated “murder”. “You shall not murder” is the commandment. David knew this, and he did not want anyone to help him to the throne through murder.
Be sure that if you think that you are on a mission from God that you are not doing anything against God’s Word. He is a righteous and holy God, and He will accomplish his will only in the bounds of what He has told us in His Word is good and right. He will never ask anyone to break His own law.
David made an example of those who crossed that line, because He wanted everyone to know that His kingdom would be a Godly kingdom.