2 Samuel 3 1
That was the beginning of a long war between those who were loyal to Saul and those loyal to David. As time passed David became stronger and stronger, while Saul's dynasty became weaker and weaker.
David's Sons Born in Hebron 2
These are the sons who were born to David in Hebron:
The oldest was Amnon, whose mother was Ahinoam from Jezreel.
The second was Daniel, 
whose mother was Abigail, the widow of Nabal from Carmel.
The third was Absalom, whose mother was Maacah, the daughter of Talmai, king of Geshur.
The fourth was Adonijah, whose mother was Haggith.
The fifth was Shephatiah, whose mother was Abital.
The sixth was Ithream, whose mother was Eglah, David's wife.
These sons were all born to David in Hebron.
Abner Joins Forces with David 6
As the war between the house of Saul and the house of David went on, Abner became a powerful leader among those loyal to Saul.
One day Ishbosheth, 
Saul's son, accused Abner of sleeping with one of his father's concubines, a woman named Rizpah, daughter of Aiah.
Abner was furious. "Am I some Judean dog to be kicked around like this?" he shouted. "After all I have done for your father, Saul, and his family and friends by not handing you over to David, is this my reward—that you find fault with me about this woman?
May God strike me and even kill me if I don't do everything I can to help David get what the LORD has promised him!
I'm going to take Saul's kingdom and give it to David. I will establish the throne of David over Israel as well as Judah, all the way from Dan in the north to Beersheba in the south."
Ishbosheth didn't dare say another word because he was afraid of what Abner might do.
Then Abner sent messengers to David, saying, "Doesn't the entire land belong to you? Make a solemn pact with me, and I will help turn over all of Israel to you."
"All right," David replied, "but I will not negotiate with you unless you bring back my wife Michal, Saul's daughter, when you come."
David then sent this message to Ishbosheth, Saul's son: "Give me back my wife Michal, for I bought her with the lives 
of 100 Philistines."
So Ishbosheth took Michal away from her husband, Palti 
son of Laish.
Palti followed along behind her as far as Bahurim, weeping as he went. Then Abner told him, "Go back home!" So Palti returned.
Meanwhile, Abner had consulted with the elders of Israel. "For some time now," he told them, "you have wanted to make David your king.
Now is the time! For the LORD has said, `I have chosen David to save my people Israel from the hands of the Philistines and from all their other enemies.'"
Abner also spoke with the men of Benjamin. Then he went to Hebron to tell David that all the people of Israel and Benjamin had agreed to support him.
When Abner and twenty of his men came to Hebron, David entertained them with a great feast.
Then Abner said to David, "Let me go and call an assembly of all Israel to support my lord the king. They will make a covenant with you to make you their king, and you will rule over everything your heart desires." So David sent Abner safely on his way.
Joab Murders Abner 22
But just after David had sent Abner away in safety, Joab and some of David's troops returned from a raid, bringing much plunder with them.
When Joab arrived, he was told that Abner had just been there visiting the king and had been sent away in safety.
Joab rushed to the king and demanded, "What have you done? What do you mean by letting Abner get away?
You know perfectly well that he came to spy on you and find out everything you're doing!"
Joab then left David and sent messengers to catch up with Abner, asking him to return. They found him at the well of Sirah and brought him back, though David knew nothing about it.
When Abner arrived back at Hebron, Joab took him aside at the gateway as if to speak with him privately. But then he stabbed Abner in the stomach and killed him in revenge for killing his brother Asahel.
When David heard about it, he declared, "I vow by the LORD that I and my kingdom are forever innocent of this crime against Abner son of Ner.
Joab and his family are the guilty ones. May the family of Joab be cursed in every generation with a man who has open sores or leprosy 
or who walks on crutches 
or dies by the sword or begs for food!"
So Joab and his brother Abishai killed Abner because Abner had killed their brother Asahel at the battle of Gibeon.
David Mourns Abner's Death 31
Then David said to Joab and all those who were with him, "Tear your clothes and put on burlap. Mourn for Abner." And King David himself walked behind the procession to the grave.
They buried Abner in Hebron, and the king and all the people wept at his graveside.
Then the king sang this funeral song for Abner:
"Should Abner have died as fools die?
Your hands were not bound;
your feet were not chained.
No, you were murdered—
the victim of a wicked plot."
All the people wept again for Abner.
David had refused to eat anything on the day of the funeral, and now everyone begged him to eat. But David had made a vow, saying, "May God strike me and even kill me if I eat anything before sundown."
This pleased the people very much. In fact, everything the king did pleased them!
So everyone in Judah and all Israel understood that David was not responsible for Abner's murder.
Then King David said to his officials, "Don't you realize that a great commander has fallen today in Israel?
And even though I am the anointed king, these two sons of Zeruiah—Joab and Abishai—are too strong for me to control. So may the LORD repay these evil men for their evil deeds."